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

Lesson 6.5Evaluating Algebraic Expressions

Apply Day · Set BSecond form · new problems, same idea

Mastery check☐ Exceeds☐ Meets target☐ Needs practice
Name Date Period

Learning target I can write an algebraic expression for a real situation and evaluate it for a given value of the variable.

Remember6.5 · Part II

Writing & Evaluating Algebraic Expressions

  1. Define the variable to represent the unknown quantity
  2. Translate mathematical phrases into operations, coefficients, and constants
  3. Evaluate by substituting given numerical values for the variable

Words: Variable (Variable)Algebraic Expression (Expresión algebraica)Coefficient (Coeficiente)Constant (Constante)Like terms (Términos semejantes)

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

    Which expression represents 'the product of 6 and a number n'?

    1. A6n
    2. B6 + n
    3. Cn − 6
    4. Dn ÷ 6
    Show your work
  2. 2Circle the letter of the best answer. Show how you know.

    Which expression represents '9 less than a number y'?

    1. Ay − 9
    2. B9 − y
    3. Cy + 9
    4. D9y
    Show your work
  3. 3Circle the letter of the best answer. Show how you know.

    Which expression represents 'the sum of a number m and 15'?

    1. Am + 15
    2. Bm − 15
    3. C15m
    4. Dm ÷ 15
    Show your work
Part 2Apply itreal-world problems
  1. 4Complete each step, then write the final answer.

    Evaluate 5n + 2 when n = 7.

    Show your work
    Final answer:
  2. 5Complete each step, then write the final answer.

    Evaluate 4.5m + 12 when m = 8.

    Show your work
    Final answer:
  3. 6Complete each step, then write the final answer.

    The expression 6n + 5 has a value of 41. Try n = 5, 6 and 7. Which value of n works?

    Show your work
    Final answer:
  4. 7Complete each step, then write the final answer.

    A plant is 5 inches tall. It grows 2 inches each week. Let w be the number of weeks. Write an expression for its height. How tall is it after 8 weeks?

    Show your work
    Final answer:
  5. 8Complete each step, then write the final answer.

    Write an expression for “15 less than 3 times a number n.” Evaluate it when n = 9.

    Show your work
    Final answer:
  6. 9Complete each step, then write the final answer.

    A school sells T-shirts for $12 each. Each shirt costs $7 to make, plus a $40 setup fee one time. Write an expression for the profit on s shirts. What is the profit for 20 shirts?

    Show your work
    Final answer:
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