Grade 6 Mathematics · Unit 6: Numerical and Algebraic ExpressionsStandard 6.AT.7

Lesson 6.66.6 Small Group · Group 2

Group 2 · Set BSecond challenge form · new problems, same idea

Mastery check☐ Exceeds☐ Meets target☐ Needs practice
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Learning target I can show that two expressions are equivalent by simplifying and combining like terms, explain why the method works, and use it on a problem I have not seen before.

Remember6.6 Small Group · Group 2

A matching test is not proof, but one test that does not match shows two expressions are not equivalent. Combining like terms shows they always match. Two expressions are equivalent only if they match for every value. One value that does not match proves they are not.

Words: Equivalent Expressions (Expresiones equivalentes)Equivalent (Equivalente)Simplify (Simplificar)Like Terms (Términos semejantes)Combine (Combinar)

Part 1Understand the ideamodels and meaning
  1. 1Circle the letter of the best answer. Show how you know.

    A gym fee is 2(x + 6) dollars for x months. Which expression is equivalent?

    1. A2x + 12
    2. B2x + 6
    3. Cx + 12
    4. D8x
    Show your work
Part 2Apply itreal-world problems
  1. 2Complete each step, then write the final answer.

    Mia says 3(x + 2) and 3x + 2 are equivalent. Find the value of 3(x + 2) when x = 4.

    Show your work
    Final answer:
  2. 3Complete each step, then write the final answer.

    Lee says 5x + 3 and 8x are equivalent because both equal 8 when x = 1. Test x = 2. What is 5x + 3 when x = 2?

    Show your work
    Final answer:
  3. 4Complete each step, then write the final answer.

    What number goes in the box so that 3(x + ☐) is equivalent to 3x + 21? Check your answer with x = 2.

    Show your work
    Final answer:

Explain your thinkingBen tested three values and all of them matched. Is that a proof? What is the best way to prove two expressions are equivalent?

How did it go? ☐ 4 · I can teach it☐ 3 · I've got it☐ 2 · I need a hint☐ 1 · I need help