Unit 5, Lesson 13
Expressions with Rational Numbers
Grade 7
13.1
Warm-up
Decide mentally whether each statement is true.
- is negative.
13.2
Activity
Your teacher will give you a set of cards. Take turns with your partner to match two expressions with the same value.
- For each match that you find, explain to your partner how you know it’s a match.
- For each match that your partner finds, listen carefully to their explanation. If you disagree, discuss your thinking and work to reach an agreement.
13.3
Activity
-
For each set of values for and , evaluate the given expressions, and record your answers in the table.
6 -6 -6 -
When and , which expression:
has the largest value?
has the smallest value?
is the closest to 0?
-
When and , which expression:
has the largest value?
has the smallest value?
is the closest to 0?
-
When and , which expression:
has the largest value?
has the smallest value?
is the closest to 0?
13.4
Activity
Student Lesson Summary
We can represent sums, differences, products, and quotients of rational numbers (and combinations of these) with numerical and algebraic expressions.
Sums:
Differences:
Products:
Quotients:
We can write the product of two numbers in different ways.
- By putting a little dot between the factors, like this: .
- By putting the factors next to each other without any symbol between them at all, like this: .
We can write the quotient of two numbers in different ways as well.
- By writing the division symbol between the numbers, like this: .
- By writing a fraction bar between the numbers, like this: .
When we have an algebraic expression like and are given a value for the variable, we can find the value of the expression. For example, if is 2, then the value of the expression is -4.25, because .
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