Are you ready to strengthen your pre-algebra skills? One skill that is essential for algebra is figuring out unknown amounts. In Section 4.1, you will begin to think about how to do so. You will use variables to represent unknown quantities and will use what you know about a problem to find the value of these variables.
In Section 4.2, you will move from mystery numbers to a mystery mascot. With your class, you will work to enlarge the mystery mascot. Then you will learn how to enlarge or reduce figures while keeping their shapes the same. You will use ratios to compare the side lengths of figures to determine if they are the same shape.
As students move into Chapter 4, they should be starting to use the mathematical practices with more automaticity. It should only take a gentle reminder from you to attend to precision in their communication with each other. They should become more comfortable constructing viable arguments and critiquing the reasoning of others as you encourage discourse during class. Students should now want to make sense of the problems that you ask them to attempt and they should be starting to show more and more perseverance in solving them.
In this chapter, you will guide students to look for and make use of more mathematical structures as they make connections and build understanding. They will also begin to model with mathematics.
6.EE.2a. Write expressions that record operations with numbers and with letters standing for numbers. For example, express the calculation “Subtract y from 5” as 5 – y.
6.EE.2c. Evaluate expressions at specific values of their variables. Include expressions that arise from formulas used in real-world problems. Perform arithmetic operations, including those involving whole number exponents, in the conventional order when there are no parentheses to specify a particular order (Order of Operations). For example, use the formulas V = s3 and A = 6s2 to find the volume and surface area of a cube with sides of length s = 1/2.
6.EE.4. Identify when two expressions are equivalent (i.e., when the two expressions name the same number regardless of which value is substituted into them). For example, the expressions y + y + y and 3y are equivalent because they name the same number regardless of which number y stands for.
6.EE.6. Use variables to represent numbers and write expressions when solving a real-world or mathematical problem; understand that a variable can represent an unknown number, or, depending on the purpose at hand, any number in a specified set.
6.RP.1. Understand the concept of a ratio and use ratio language to describe a ratio relationship between two quantities. For example, “The ratio of wings to beaks in the bird house at the zoo was 2:1, because for every 2 wings there was 1 beak.” “For every vote candidate A received, candidate C received nearly three votes.”