Lesson 5 Find the Difference

- Let’s find differences within 10.

Warm-up Number Talk: Missing Value Within 10

Find the number that makes each equation true.

$6 +$ $= 10$
10-6=
$8 +$ $= 10$
$10 - 2 =$

Activity 1 Different Ways to Find the Difference

Mai, Diego, and Noah find the value of $10 - 6$ .

Diego says, “I can take away.”
What does Diego mean?
Be ready to explain your thinking in a way that others will understand.
Mai says, “I can count on.”
What does Mai mean?
Be ready to explain your thinking in a way that others will understand.
Noah says, “I can use what I know about $6 + 4$ to help me.”
What does Noah mean?
Be ready to explain your thinking in a way that others will understand.

Activity 2 Subtraction Number Strings

Problem 1

Two students talking.

Find the value of each difference in the subtraction string.
Explain what you notice.

Set 1:

$6 - 1$
$6 - 2$
$6 - 3$
$6 - 4$

Problem 2

What do you notice?
Why do you think this happens?
Be ready to explain your thinking in a way that others will understand.

Problem 3

Find the value of each difference in the subtraction string.
Explain what you notice.

Set 2:

$9 - 8$
$9 - 7$
$9 - 6$
$9 - 5$

Problem 4

What do you notice?
Why do you think this happens?
Be ready to explain your thinking in a way that others will understand.

Activity 3 The Value of the Difference

Find the value of each difference.

$9 - 6$
$10 - 3$
$7 - 3$
$9 - 5$
$8 - 6$
$6 - 5$
$9 - 4$
$10 - 7$

Practice Problem

Problem 1

Find the value of each expression.
Show your thinking using drawings, numbers, or words.

$4 + 3$
$7 - 3$
$8 - 2$