2020
CK-12 Interactive Middle School Math for CCSS

6th Grade - Gateway 2

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Gateway Ratings Summary

Rigor & Mathematical Practices

Gateway 2 - Partially Meets Expectations
72%
Criterion 2.1: Rigor
7 / 8
Criterion 2.2: Math Practices
6 / 10

The instructional materials reviewed for CK-12 Interactive Middle School Math 6 for CCSS partially meet expectations for rigor and practice-content connections. The instructional materials meet expectations for rigor by developing conceptual understanding of key mathematical concepts, giving attention throughout the year to procedural skill and fluency, and balancing the three aspects of rigor. The materials partially meet expectations for practice-content connections as they explicitly attend to the specialized language of mathematics and partially meet expectations for the remainder of the indicators in practice-content connections.

Criterion 2.1: Rigor

7 / 8

Rigor and Balance: Each grade's instructional materials reflect the balances in the Standards and help students meet the Standards' rigorous expectations, by helping students develop conceptual understanding, procedural skill and fluency, and application.

The instructional materials reviewed for CK-12 Interactive Middle School Math 6 for CCSS meet expectations for rigor. The instructional materials develop conceptual understanding of key mathematical concepts, give attention throughout the year to procedural skill and fluency, and do not always treat the three aspects of rigor together or separately. The materials are partially designed so that teachers and students spend sufficient time working with engaging applications of mathematics.

Indicator 2a

2 / 2

Attention to conceptual understanding: Materials develop conceptual understanding of key mathematical concepts, especially where called for in specific content standards or cluster headings.

The instructional materials reviewed for CK-12 Interactive Middle School Math 6 for CCSS meet expectations for developing conceptual understanding of key mathematical concepts, especially where called for in specific standards or cluster headings. The materials include problems and questions that develop conceptual understanding throughout the grade-level.

Chapters 1 and 2 provide students with opportunities to develop conceptual understanding of understanding ratio concepts and use ratio reasoning to solve problems (6.RP.A) with the use of Interactives and Inline Questions. Examples include:

  • In Lesson 1.2, Activity 2: Tape Diagrams, students manipulate a tape diagram to build a conceptual understanding of how two quantities form a relationship in the form of ratios. The teacher notes describe what the students do independently by stating, “This gives students a chance to practice visualizing and identifying ratios.” (6.RP.1)
  • In Lesson 1.5, students complete tables of equivalent ratios and use values to answer questions (6.RP.3a). In Activity 2, students complete a table on beats in a sample song: “How many beats are there in this 12 second song sample? Use the table to find the total numbers of beats for 60 seconds of the song.” Once the table is completed, students answer the following inline questions: “1. What is the relationship between 24 seconds and 12 seconds? How can you use this to find the number of beats in 24 seconds? 2. For 12 seconds, the ratio of number beats to number of seconds is ___:12. 3. Since 48 seconds is four times 12 seconds, the number of beats in 48 seconds is ___times the number of beats in 12 seconds. There are ___ beats in 48 seconds. This works because the ratios 25:12 and _____are equivalent.” Examples of practice questions for students to complete are problem 2, “If there are six campers per tent, how many tents for 30 campers?” and problem 10, “Complete the table 72:48, 36:24, 24:16, ___:12, 12:8.”
  • In Lesson 2.8, Activity 2, students further develop their understanding of ratios by using a double number line to fill in the blanks based on a ratio and answering questions. For example, Item 2 states, “There are 4 thousand (4,000) pet tarantulas in the US. The number of turtles is 150% the number of tarantulas. How many pet turtles are there?” (6.RP.3)

Chapter 3 has multiple opportunities for students to work independently to build conceptual understanding of applying and extending previous understandings of multiplication and division to divide fractions by fractions (6.NS.1) through the use of Interactives. Examples include:

  • In Lesson 3.3, Activity 3, students develop understanding of dividing a fraction by a fraction using a visual diagram. The teacher directions state how the students will use the interactive in the activity to build this conceptual understanding, “Students are given a tape diagram and slider and a fraction (starting at 1). Students can use the slider to divide the diagram and the resulting fraction will appear above the slider.” (6.NS.1)
  • In Lesson 3.6, Activity 1, students further develop their understanding of division of fractions through an interactive where students manipulate a scale of a map to connect division with fractions. The interactive introduces this to students by stating, “Pirate Captain Jim Hawkins designs a treasure map and draws out a 1 mile by 1 mile map of an island. He divides his map into smaller squares to make it easier to read.” (6.NS.1)
  • In Lesson 3.9, Warm-Up, students work with an interactive to divide fractions in the real world situation of a water gun fight. The directions for the students explain, “Use the interactive to see how many times you can reload the water gun before you have to run to fill the bucket up with more water. Through this lesson, you will use tape diagrams to model fraction division and find the quotients.” (6.NS.1) 

Chapters 6 and 7 have multiple opportunities for students to work independently to build conceptual understanding of applying and extending previous understandings of arithmetic to algebraic expressions and reasoning about and solving one-variable equations and inequalities (6.EE.A,B) through the use of Interactives. Examples include:

  • In Lesson 6.9, Activity 3, students factor expressions using the distributive property. Inline question 4 states, “Write an equivalent expression for $$20x+30$$ by dividing both terms by 5,” and question 5 states, “Look at the expression $$12x+20$$. Select the equivalent expressions.” (6.EE.3)
  • In Lesson 7.4, Activity 1, students develop understanding of solving equations in the form of $$20x+30$$ through an interactive. In the interactive, students use numbers to try to isolate and solve for x. The student directions state, “Answering the question above will require knowledge of multiplication equations. Multiplication equations have many similarities with addition equations. Use the interactive below to explore these similarities and to practice solving multiplication equations visually.” (6.EE.7)

Indicator 2b

2 / 2

Attention to Procedural Skill and Fluency: Materials give attention throughout the year to individual standards that set an expectation of procedural skill and fluency.

The instructional materials reviewed for CK-12 Interactive Middle School Math 6 for CCSS meet expectations for attending to those standards that set an expectation of procedural skill and fluency. The instructional materials develop procedural skill and fluency and provide opportunities for students to independently demonstrate procedural skill and fluency throughout the grade level, especially where called for by the standards (6.NS.2,3; 6.EE.1,2).

In Chapter 4, the materials develop and students independently demonstrate procedural skill and fluency in adding, subtracting, multiplying, and dividing multi-digit numbers and decimals with standard algorithms (6.NS.2,3). Examples include:

  • In Lesson 4.2, “there are widget interactives that will guide students through the standard method of adding and subtracting decimals. Students can work with an unlimited amount of times, so they should practice the method until they are comfortable before moving onto the real-world examples” (purple text). The first CK-12 Widget Interactive gives students step-by-step procedures on adding decimals, for example “8.153 + 1.535.” Students independently practice with numerous problems before moving onto the second part of the interactive where they now have to “carry over/borrow” a 1, for example “$$7.242+1.846$$,” but the same step-by-step procedures are followed. Again, the student can practice independently as much as needed. The second CK-12 Widget Interactive focuses on subtracting decimals, again giving the same step-by-step procedures. The problems get increasingly more difficult,  for example, “$$2.972 - 1.141$$; $$6.268 - 1.948$$,” and students can practice independently with an unlimited amount of problems. (6.NS.3)
  • In Lesson 4.4, Activity 2 Interactive, students multiply multi-digit numbers. The teacher directions state, “This interactive gives students a walk through for multiplying two decimals. Use the text boxes to evaluate the product one step at a time, after a student has typed in their answer they should press the enter key to see if it is correct. If it is wrong, it will turn red and students can try again. Once a correct answer is entered it will turn black and a new text box will appear.” In Multiplying Decimals with the Standard Method, students independently demonstrate procedural skill with multiplying decimals in all of the Review Questions. For example, Review Question 7, “$$1.7 × 9.691 =$$ ____.” (6.NS.3)
  • In Lesson 4.6, the Warm-Up: Practice Long Division “gives the student practice dividing with the standard method.” The interactive provides the student step-by-step procedures on long division with problems such as 679 divided by 7. In Activity 1, Practice More Difficult Long Division increases the level of difficulty, for example “9460 divided by 43,” but still gives the same step-by-step procedures. In Lesson 4.6, Activity 1 Interactive, students demonstrate fluency in dividing multi-digit numbers as students, “Use these interactives to practice some more challenging and advanced long division problems! Can you answer the most difficult ones? 180482 = ? and 8692505 = ?” (6.NS.2)

In Chapter 6, the materials develop and students independently demonstrate procedural skill in writing and evaluating numerical expressions (6.EE.1) and writing, reading, and evaluating expressions in which letters stand for numbers (6.EE.2). Examples include:

  • In Lesson 6.1, Activity 1: Can you make the math?, students write an expression from a word phrase, for example Inline Question 1 states, “Which of the following correctly displays ‘one-third of the sum of a number and 5’?” answer choices: a. $$\frac{1}{3}(x+5)$$; b. $$\frac{1}{3}+x+5$$; c.$$\frac{1}{3}x+5$$; d. $$\frac{1}{3x}+5$$,” and Practice Questions 2 states, “Choose an expression for the following phrase: Four less than a number.” (6.EE.2) 
  • In Lesson 6.2, Activity 2 Interactive, students evaluate expressions involving whole-number exponents using sliders to see how the exponent is used to represent multiplication. The teacher directions state, “For this interactive, students can experiment with different values raised to an exponent and see the resulting expanded expression. Students can use the red and blue slider to adjust the values of the exponent.” (6.EE.1)
  • In Lesson 6.3, Activity 3 Interactive, students demonstrate fluency in writing expressions involving whole-number exponents using the interactive to determine how many lights are needed and identifying it as an expression with exponents. The directions for students state, “Use the interactive below to figure out how many strings of LED lights you would need to decorate the Christmas tree on an ugly Christmas sweater.” (6.EE.1)
  • In Lesson 6.4, Activity 3: What picture does connect the dots make? states, “This interactive helps students practice evaluating expressions using order of operations with an added bonus of drawing a picture. An expression is given and students can use the buttons at the bottom of the window to choose which operand that should be used next.” For example, Inline Question 1 states, “Which order of operations would you do FIRST in this type of problem? $$2(4 + 3)2 ÷ 7$$.” (6.EE.1)

Indicator 2c

1 / 2

Attention to Applications: Materials are designed so that teachers and students spend sufficient time working with engaging applications of the mathematics, without losing focus on the major work of each grade

The instructional materials reviewed for CK-12 Interactive Middle School Math 6 for CCSS partially meet expectations for being designed so that teachers and students spend sufficient time working with engaging applications of mathematics. The materials include multiple opportunities for students to engage in routine application of grade-level skills and knowledge, within instruction and independently. The materials include one non-routine application problem within instruction, but students do not demonstrate independent application of mathematics in non-routine situations.

Examples of students engaging in routine application of grade-level skills and knowledge, within instruction and independently, include: 

  • In Chapters 1 and 2, students engage in familiar real-world scenarios and demonstrate the application of ratio and rate reasoning through the use of questions and interactives (6.RP.3). For example, in Lesson 1.3, Activity 4, Inline Question 1 states, “You mix 12 cups of brown paint by using 3 cups of yellow paint to 4 cups of red paint to 5 cups of blue paint. After painting a portion of a fence you realize that you need more of the same color paint to finish the fence. This time you want to make 26 cups. How many cups of each color do you need?” The answers are multiple choice, and students can use the interactive to check each choice. Also, in Lesson 2.9, Activity 2 states, “1. What do you notice about the relationship between the decimal value and its percent? A. The percent is 10 times the decimal value. B. The percent is 100 times the decimal value. C. The percent is greater than the decimal value.”
  • In Chapter 7, students write and solve equations of the form $$x + p = q$$ and $$px = q$$ (6.EE.7) and use variables to represent two quantities in a real-world problem that change in relationship to one another through the use of interactives (6.EE.9). For example, In Lesson 7.3, Activity 1 Interactive states, “The typical lithium element has 3 protons and 7 total protons and neutrons. You can represent this relationship using an equation: Protons + Neutrons = Mass Number, $$P + N = M$$. Substitute our known values to produce the following: $$3 + N = 7$$. Use this equation in the interactive below to visually identify the number of neutrons in the lithium atom.” Also, Lesson 7.8, Activity 1 states, “This interactive gives students the chance to use the formula distance = rate x time. To start, select an animal from the drop down menu. The rate will be given at the top and below the students can fill out the table of values for the distance that the animal travels at certain times. If an incorrect value is entered, it will turn red. Once a correct value is entered it will turn black. Students can try different animals by clicking the reset button under the interactive window.” Inline Questions help to formulate an equation, for example, Inline Question 2 states, “Complete the table for the cheetah, The cheetah travels at 105 feet per second. Write an equation for the cheetah’s distance d over time t.”
  • In Lesson 9.4, Activity 2, students apply their knowledge of the area of a triangle in real-world contexts (6.G.1) as they answer, “Marielle wants to paint a triangular section of her house. One gallon of paint covers 400 square feet. Use the interactive below to find the dimensions of the triangle section.” Inline Question 4 includes, “If Marielle wants to use three layers of paint on the triangular section of her house, how many gallons will be needed?” 
  • In Lesson 10.5, Activity 3, Inline Question 4, students use mean and median to analyze a set of data as they answer, “Look at Helena’s time again: 17.44, 17.5, 17.85, 17.99, 18.11, 18.25, 31.23, 35.55. Remember, the mean time is 21.74 seconds. The median time is 18.05 seconds. What can you conclude by comparing the mean (average) to median (middle)?”

The non-routine application problem within instruction is in Chapter 3. In Lesson 3.9, Activity 3 Interactive, the teacher's directions include, “In this interactive, students will create their own division of fractions problem and use a visual model to help solve the problem. To begin, students can type in the two fractions they want to divide. After the fractions are entered the tape diagrams will show the fraction represented as a diagram. Students can click and drag the red diagram over the blue diagram, then the division equation will appear. Click the Show divisions button to see how the division is represented on the diagram. Students can then type in their answer to the division statement in the textbox. Students will type in the value of the numerator, then the value for the denominator.” (6.NS.1)

Indicator 2d

2 / 2

Balance: The three aspects of rigor are not always treated together and are not always treated separately. There is a balance of the 3 aspects of rigor within the grade.

The instructional materials reviewed for CK-12 Interactive Middle School Math 6 for CCSS meet expectations that the three aspects of rigor are not always treated together and are not always treated separately. All three aspects of rigor are present independently throughout the program materials. Examples include:

  • In Lesson 3.1, Activity 1, students develop conceptual understanding of division of fractions with the interactive, Can You Design a Flag?. The materials state, “Students are given an adjustable flag that measures $$1\frac{1}{5}$$ m. Students can change the thickness of each portion by clicking and dragging the red points at the bottom of the flag. As the sections are adjusted, the fractions at the bottom will change, showing how much of the flag that portion is taking up. Students can toggle between a flag with 6 stripes and 3 stripes by clicking the button at the bottom right hand corner of the screen.” (6.NS.1)
  • In Lesson 4.7, students demonstrate fluency with dividing decimals by decimals. For example, the practice problems include, “Find the quotient $$31.93÷3.1$$. a) 10.3 b) 9.4 c) 12.6 d) 14.7.” (6.NS.3)
  • In Lesson 1.5, Activity 3, Inline Questions, students demonstrate application of ratios in the Interactive about bicycles. Some examples include: “1. What is the relationship between 16 teeth in the back gear with 8 teeth in the back gear? How can you use this to find the number of teeth in the front gear for every 8 teeth in back gear? A. Since 8 back teeth is half the number of 16 back teeth, you can divide 44 by 2 to get the number of front teeth associated with 8 back teeth. B. Since 16 back teeth is two times 8 back teeth, you can multiply 44 by 2 to get the number of front teeth associated with 8 back teeth. C. Since 8 back teeth is 16 back teeth minus 8, you can subtract 8 from 44 to get the number of front teeth associated with 8 back teeth. D. Since 16 back teeth divided by 2 is 8 back teeth, you can divide 44 by 2 to get the number of front teeth associated with 8 back teeth. 2. Since 12 is halfway between 8 and 16, the number of teeth in the front gear will be halfway between 55 and the number of teeth associated with 8 back teeth. True/False” (6.RP.3)

Multiple aspects of rigor are engaged simultaneously to develop students’ mathematical understanding of a single topic/unit of study throughout the materials. Examples include:

  • In Lesson 1.3, students develop a conceptual understanding of equivalent ratios through tape diagrams. In the Warm Up: What does “miles per gallon” mean?, students use the interactive to adjust miles and gallons to create equivalent ratios. Inline Question 1 states, “Which ratio of miles to gallon would a person driving the truck like to have?” In Activity 4: How can you mix the color brown with paints?, students apply their understanding of equivalent ratios to mixing paint. Inline Question 1 states, “You mix 12 cups of brown paint by using 3 cups of yellow paint to 4 cups of red paint to 5 cups of blue paint. After painting a portion of a fence you realize that you need more of the same color paint to finish the fence. This time you want to make 26 cups. How many cups of each color do you need?”
  • In Lesson 2.6, students develop a conceptual understanding of percentages being a ratio per 100 in the interactive in Activity 1, How Much of a Century Have You Lived? The materials state, “To start, students are given a number line with dates from 200 to 2100 in ten year increments. Below there is a text box where students can input their birthday (must be between 2000 and the current date) and press the enter key. Students will see a red line on the timeline showing the imputed date to today, and above that, the percent.” Inline Question 5 states, “(Fill in the blank) When you are 20 years old you will have lived __% of a century. When you are 50 years old you will have lived __% of a century. When you are 100 years old you will have lived __% of a century. When you are 101 years old you will have lived __% of a century.” In Practice, students develop procedural skills as they independently determine percentages as numbers out of 100. The materials state, “Write the following percent as a ratio out of 100. 3% a) $$\frac{4}{100}$$ b) $$\frac{3}{100}$$ c) $$\frac{2}{100}$$ d) $$\frac{1}{100}$$.”

Criterion 2.2: Math Practices

6 / 10

Practice-Content Connections: Materials meaningfully connect the Standards for Mathematical Content and the Standards for Mathematical Practice

The instructional materials reviewed for CK-12 Interactive Middle School Math 6 for CCSS partially meet expectations for practice-content connections. The materials explicitly attend to the specialized language of mathematics. The materials partially: identify and use the Standards for Mathematical Practice (MPs) to enrich mathematics content; attend to the full meaning of each MP; provide opportunities for students to construct arguments and analyze the arguments of others; and assist teachers in engaging students to construct viable arguments and analyze the arguments of others.

Narrative Only

Indicator 2e

1 / 2

The Standards for Mathematical Practice are identified and used to enrich mathematics content within and throughout each applicable grade.

The instructional materials reviewed for CK-12 Interactive Middle School Math 6 for CCSS partially meet expectations for identifying and using the Standards for Mathematical Practice (MPs) to enrich mathematics content within and throughout the grade-level. The materials state that teachers should use a few MPs in each lesson, but each lesson does not include guidance on which MPs to use. MPs are explicitly identified in the Teacher Notes, but MPs 7 and 8 are not identified in the materials. Also, no MPs are identified in Chapters 3 and 10, and they are only identified once in Chapters 6, 7, and 8.

Examples of the materials identifying and using the MPs to enrich the mathematics content include:

  • MP1: This was identified two times in the materials. Lesson 4.6 states, “Students will then work through some division problems within a context and work through a long division puzzle (MP1). If students are still not comfortable with long division, they can work through the widgets at the beginning as many times as they wish. For students who do not need to spend as much time practicing, encourage them to try to challenge problems at the end of the lesson.” Also, Lesson 4.9 states, “students will learn about least common multiples. Students will work through real-world examples and puzzles to practice finding the least common multiple of two or more numbers (MP1).”
  • MP2: Lesson 1.1 states, “In this lesson, students will learn that a ratio is used to describe the relationship between two quantities.Throughout the lesson it would be helpful to allow them to use the language. This will help them understand how they can use ratio language in everyday situations. With partners, they can compare the number of students, chairs, desks, windows, whiteboards, etc. using ratio language (MP2).”
  • MP4: Lesson 7.6 states, “As students write their equations, they should be thinking about the independent and dependent variables to help them understand that the equations represent the relationship between the two variables. Once students have written the equations, they should practice interpreting what each part means within the context of the situation (MP4).”
  • MP6: Lesson 2.3 states, “In this lesson, students will review long division and apply it to solving unit pricing problems. Students will be filling out tables, but it is important for them to practice using the language associated with unit rates. Students can practice reviewing their answers with a partner using ‘price per item’ phrases (MP6).”

There are some instances in which the Mathematical Practices are labeled but do not enrich the content. For example, in Lesson 4.4, MP5 is identified. Students use the Interactive to solve the equation, but they can type numbers into the Interactive until it shows the correct answer, which means students are not using tools strategically to enrich their work with dividing decimals using the standard algorithm. In Activity 2, this process is described in the Teacher Notes, “This interactive gives students a walk through for multiplying two decimals. Use the text boxes to evaluate the product one step at a time, after a student has typed in their answer they should press the enter key to see if it is correct. If it is wrong, it will turn red and students can try again. Once a correct answer is entered it will turn black and a new text box will appear. Students can use the text boxes above each number being multiplied to help with their calculation, but it is not necessary. Once students have multiplied and added all the numbers, they will be able to place the decimal by clicking and dragging the red point to one of the red circles in between each of the numbers in the final answer. Once the student has placed the decimal, click the Check button.”

Indicator 2f

1 / 2

Materials carefully attend to the full meaning of each practice standard

The instructional materials reviewed for CK-12 Interactive Middle School Math 6 for CCSS partially meet expectations for carefully attending to the full meaning of each practice standard. The materials do not attend to the full meaning of two MPs.

Examples of the materials not attending to the full meaning of MP5 include, but are not limited to: 

  • In Lesson 4.4, the Introduction includes, “Students will continue practicing multiplying decimals; however, this lesson focused on the standard method. Students will begin working with an interactive similar to the ones found in the previous lesson, Multiplying Decimals with Diagrams. There is a widget interactive that will guide students through the standard method of multiplying decimals (MP5).” Students do not select which tools to use as they are provided.
  • In Lesson 5.4, Activity 2, “In the previous activity, we saw that numbers on both sides of the number line are related. The overlapping numbers in the interactive above are opposite numbers. The opposite of a number, also known as the additive inverse, comes from the additive inverse property. The additive inverse property states that for any real number n, there exists an additive inverse which is the same distance from zero in the opposite direction. Additionally, the sum of a number and its additive inverse will always be zero: n + (-n) = 0. A trick is to change the sign of the number, for example, the opposite of 7 is -7 and the opposite of -15 is 15. Use the interactive below to explore opposite numbers.” Students do not select a tool for this investigation.

Examples of the materials not attending to the full meaning of MP8 include, but are not limited to:

  • In Lesson 3.9, students use tape diagrams to practice dividing fractions. In the Warm-Up, students answer, “How many times can you reload the water gun?” The materials include, “Use the interactive to see how many times you can reload the water gun without having to run to fill the bucket up with more water. Through this lesson, you will use tape diagrams to model fraction division and solve for the quotients.” Students are given the tape diagram that represents the expression and the steps to solve it. Students do not generalize a pattern from this activity.
  • In Lesson 4.4, Activity 1, Inline question 3, students answer, “What pattern do you see when finding the number of Newtons? Remember that you multiply the number of kilograms by 10 to find the Newtons. Red Car: 0.454 kgs, 4.54 Newtons; Green Car: 0.681 kgs, 6.81 Newtons; Blue Car: 1.362 kgs, 13.62 Newtons. a) Multiplying by 10 adds a zero to the end of the number. b) Multiplying by 10 moves the decimal place over to the left by 1 place. c) Multiplying by 10 moves the decimal point over to the right by 2 places. d)Multiplying by 10 moves the decimal point over to the right by 1 place.” Students choose from a finite list, which they can do by guessing, instead of generalizing a pattern from repeated reasoning.

Indicator 2g

Narrative Only

Emphasis on Mathematical Reasoning: Materials support the Standards' emphasis on mathematical reasoning by:

Indicator 2g.i

1 / 2

Materials prompt students to construct viable arguments and analyze the arguments of others concerning key grade-level mathematics detailed in the content standards.

The instructional materials reviewed for CK-12 Interactive Middle School Math 6 for CCSS partially meet expectations for prompting students to construct viable arguments and analyze the arguments of others concerning key grade-level mathematics.

The materials provide opportunities for the students to construct arguments about the content, and examples include:

  • In Lesson 1.3, Activity 4, Discussion Question, students construct an argument about how the ratio staying the same will impact the results of the paint mixing while taking equvalentance into account. The materials state, “When the total amount of paint increases and decreases but the ratio of paint colors remains equivalent, does the shade of brown change? Use the idea of equivalence to help explain why.”
  • In Lesson 2.2, Activity 3, Discussion Question, students construct an argument about the appropriate use of unit rates in relation to shark teeth. The materials state, “Use the unit rates to order the sharks from greatest number of teeth to least number of teeth. Did you need to find the unit rate to order the sharks? If not, think of an example of when you would need to find the unit rate to compare numbers of shark teeth.”
  • In Lesson 6.8, Activity 2, Discussion Question, students construct an argument to determine the appropriate time to substitute numbers in an expression. The question states, “You can only sometimes count the numbers of bumps on the spiral. When is it useful to substitute numbers into the expression to find the number of bumps?”

There are no opportunities for students to analyze the arguments of others, and examples include, but are not limited to:

  • In Lesson 1.4, Activity 1, Discussion Question, students discuss with the class but do not analyze the arguments of others. The question states, “What are the differences between a tape diagram and a number line? Discuss your answer with your class or in the CK-12 Cafe.” 
  • In Lesson 3.6, Activity 2, Discussion Question, students use mathematics to explain their thinking but do not analyze other students’ reasoning. The question states, “The largest IMAX theater in the world is in Melbourne, Australia. It is 105 feet by 75 feet. Compare the area of the largest IMAX screen with the standard IMAX screen and the "local movie theater" screen from the example.”
  • In Lesson 10.5, Warm-Up, the Discussion Question states, “What is the difference between center and variability? Discuss in class or in the CK-12 Cafe. Answers may vary. Encourage students to point out that it is not guaranteed the 50% of the data values occur above or below the mean.”
  • In Lesson 10.8, Activity 3, Discussion Question, students describe which data set to use but do not analyze the arguments of others. The question states, “The mean of the dataset is 16.92 ounces and the mean absolute deviation is approximately 1.15 ounces. Which set of statistics do you feel better describes the data: the median and the interquartile range, or the mean and the mean absolute deviation (MAD)?”

Indicator 2g.ii

1 / 2

Materials assist teachers in engaging students in constructing viable arguments and analyzing the arguments of others concerning key grade-level mathematics detailed in the content standards.

The instructional materials reviewed for CK-12 Interactive Middle School Math 6 for CCSS partially meet expectations for assisting teachers in engaging students to construct viable arguments and analyze the arguments of others concerning key grade-level mathematics. The materials include some examples of assisting teachers in engaging students to construct viable arguments and analyze the arguments of others, but there are also multiple instances where the materials do not assist teachers.

Examples of the materials assisting teachers to engage students in constructing and/or analyzing the arguments of others include:

  • In Lesson 4.8, Activity 1, Interactive Plix: GCF Using Lists, the Teacher Notes state, “The last question prompts students to construct an argument for why the GCF is always a natural number and never a fraction. You can remind students that natural numbers are whole numbers not including the number 0 (1, 2, 3, 4, etc).” 
  • In Lesson 5.1, Warm-Up: Sea Level, the Teacher Notes state, “Allow students to turn and talk and build off each other’s ideas in a whole class setting. By the end of the discourse, students should be able to articulate that the sea animals are below and the birds are above sea level, and that sea level represents 0 because it has no elevation, the other animals are located somewhere in relation to sea level.”
  • In Lesson 10.9, Activity 3, Discussion Question, the Teacher Notes state, “Answers may vary. Encourage students to use numerical evidence from the datasets to support their argument. One missing piece of information is the reason behind the two grades of 0. Perhaps the students did not know any answers or perhaps they were absent. Knowing this information would likely affect the students' stance on which side did better.”

Examples where the materials do not assist teachers to engage students in constructing and/or analyzing the arguments of others include:

  • In Lesson 3.8, Activity 2, Supplemental Questions, the Teacher Notes state, “Why is dividing by a fraction, the same as multiplying by the reciprocal of the fraction? Students will have different explanations. They may refer to the tape diagram and explain how many times a fraction can divide into a whole number. They may note that the number of parts the bars are divided into is the denominator and the groupings of the parts is the numerator.” The materials do not assist teachers in having students analyze the arguments of others.
  • In Lesson 5.3, Warm-Up, the Teacher Notes encourage students to discuss their answers to questions provided to the teachers. The Teacher Notes state, “Allow students to discuss and answer the questions. How does the use of a negative affect the meaning of the numbers above? The negative identifies whether the money is owned or owed. How does the distance from zero affect the meaning of the numbers above? The closer to zero, the smaller the debt or value. The farther from zero, the greater the debt or value.” The materials encourage discussion among students, but they do not assist teachers in having students analyze the arguments of others.
  • In Lesson 8.4, Warm-Up, Discussion Question, the Teacher Notes indicate that there may be different answers from students, but there is no assistance as to how students construct an argument about the weight. The Teacher Notes state, “Allow students to answer. Answers may vary. The beam must weigh either 18 tons or less. The beam could weigh 2 tons. The beam cannot weigh 20 tons.”

Indicator 2g.iii

2 / 2

Materials explicitly attend to the specialized language of mathematics.

The instructional materials reviewed for CK-12 Interactive Middle School Math 6 for CCSS meet expectations for explicitly attending to the specialized language of mathematics. The materials provide instruction on communicating mathematical thinking using words, diagrams, and symbols. Examples include:

  • In Lesson 1.1, the Teacher’s Edition includes, “In this lesson, students will learn that a ratio is used to describe the relationship between two quantities. They will use ratio language to describe quantities involving recipes, colored blocks, and butterflies. Throughout the lesson it would be helpful to allow students the time to practice using ratio language to describe things in the classroom (MP6).”
  • In Lesson 5.6, at the beginning of the Lesson, the Teacher Notes state, “It would be helpful to define the terms horizontal and vertical, so students can use these terms throughout the lesson to describe an object's location on a coordinate plane.”
  • In Lesson 5.7, Warm-Up, “we can describe the position of an object by the location on the x-axis number line and the y-axis number line. The location of the object can be written using the coordinate (x, y) where x is the location of the object along the x-axis and y is the location of the object along the y-axis. Use the interactive below to practice using coordinate notation.”

The materials use precise and accurate terminology and definitions when describing mathematics, and the materials also support students in using the terminology and definitions. There is no separate glossary in these materials, but definitions are found within the units in which the terms are used. The vocabulary words are in bold print. Examples include:

  • In Lesson 1.1, Activity 1, Inline Questions, Example 2, “Angie wants to bake cookies for a bake sale. The recipe says “for every 1 cup of butter use 3 cups of flour.” You can use the word ratio to show the relationship between quantities. What is the ratio of butter to flour in one batch of cookies?”
  • In Lesson 5.5, Activity 1, “The absolute value of a number is the distance of that number from zero. The absolute value of 23 is 23 because it is 23 units from zero. The absolute value of -12 is 12 because it is 12 units from zero. The absolute value symbol is written using a straight vertical line on either side of the number or expression. The absolute value of 5 is written |5|.”
  • In Lesson 10.4, the Warm Up includes, “A measure of center is a single number used to describe a set of numeric data. It describes a typical value from the data set. Measures of center include the mean and the median. The mean (or what is more commonly referred to as the average) of a data set is the sum of the data values divided by the number of data values in the set. As you saw in the warm-up, the mean can be thought of as "evening out" the data values. The range is a measure of spread. You can find the range by taking the greatest data value and subtracting the least data value. In other words, it is the difference between the maximum and minimum data point.” Activity 2 includes, “The median represents the middle value of an ordered data set. It is another measure of center.”