Grade 3 Unit
Lesson 15: Number Talk
CC BY 2021 Illustrative Mathematics®
Grade 3 Unit
Lesson 15: Number Talk
CC BY 2021 Illustrative Mathematics®
Find the value of each expression mentally.
300 + 400
300 + 437
321 + 437
425 + 514
Here are three subtraction expressions.
600 - 400
600 - 399
500 - 399
Think of at least two different ways to find the value of each difference mentally.
Write a fourth subtraction expression whose value can be found using one of the strategies you thought of.
Here are two addition expressions.
500 + 199
504 + 199
Think of at least two different ways to find the value of each sum mentally.
Write two more addition expressions whose values can be found using the strategies you thought of.
Write three subtraction expressions to complete the Number Talk.
900 - 400
Write four addition or subtraction expressions to create a Number Talk.
As mathematicians, we use patterns and things we see happening over and over again to help us reason about new problems. Describe a time today where you did that.