Lesson 16 Add Three Numbers

    • Let’s add 3 numbers.

Warm-up Number Talk: Related Expressions

Find the value of each expression mentally.

Activity 1 Match Expressions

  1. Draw a line to match expressions with the same value.

    expressions with 3 numbers

    expression

  2. If you have time… Write another expression with 3 numbers. 2 of the numbers should make 10.

    Ask your partner to think of the matching expression.

Activity 2 Is the Equation True?

Problem 1

Determine whether each equation is true or false.
Be ready to explain your reasoning in a way that others will understand.

    1. hand with thumbs up and true written underneath.
    2. hand with thumbs down and false written underneath.

    1. hand with thumbs up and true written underneath.
    2. hand with thumbs down and false written underneath.

    1. hand with thumbs up and true written underneath.
    2. hand with thumbs down and false written underneath.

    1. hand with thumbs up and true written underneath.
    2. hand with thumbs down and false written underneath.

    1. hand with thumbs up and true written underneath.
    2. hand with thumbs down and false written underneath.

Problem 2

If you have time…

  1. Make any false equations true.

  2. Write 1 equation that is true and 1 that is false.
    Switch with your partner.

Activity 3 Write Expressions

Problem 1

Write a  expression that has the same value as each expression.

Problem 2

If you have time… Write as many expressions as you can with 3 numbers that are equal to .

Practice Problem

Problem 1

Select 3 expressions that are equal to .