Section C: Practice Problems Subtract Within 1,000 using Place Value Strategies

Section Summary

Details

In this section of the unit, we learned many different ways to subtract three-digit numbers using what we know about place value. We used base-ten blocks, diagrams, and equations to show subtracting hundreds from hundreds, tens from tens, and ones from ones. We learned that when you subtract by place, you may decompose a hundred, a ten, or both. We learned that it is helpful to look closely at the numbers in an expression to plan how to decompose or to choose a method that helps us use friendly numbers or the relationship between addition and subtraction.

Base-ten Diagram for $256 - 64$

Unit Form for $726 - 558$

Subtraction using decomposition. Unit form for 726 minus 558 equals 168.

Problem 1 (Lesson 12)

Find the value of each difference.
- $325 - 19$
- $437 - 115$
Jada drew this picture to find the value of a difference. What difference did Jada calculate? Explain how you know.

Problem 2 (Lesson 13)

Find the value of each difference. Show your thinking.

$936 - 428$
$352 - 181$

Problem 3 (Lesson 14)

Jada is finding the value of $571 - 385$ . She says that she can take the ones from the ones, tens from the tens, and hundreds from the hundreds, with no decomposing. Do you agree with Jada? Explain your reasoning.

Problem 4 (Lesson 15)

Find the value of each difference. Show your thinking.

$216 - 88$
$803 - 564$

Problem 5 (Lesson 16)

Find the value of each difference in a way that makes sense to you. Show your thinking.

$747 - 295$
$811 - 255$
$600 - 378$

Problem 6 (Exploration)

Here is how Kiran found the value of $543 - 276$

$500 - 200 = 300$

$300 - 30 = 270$

$270 - 3 = 267$

Explain why Kiran’s method works.
Use Kiran’s method to find $325 - 276.$

Problem 7 (Exploration)

Choose a three-digit number so that subtracting by place value is a good strategy for finding the value of
$637 -$ . Explain your reasoning and find the value of the difference.
Choose a three-digit number so that adding on to the smaller number is a good strategy for finding the value of
$637 -$ . Explain your reasoning and find the value of the difference.
Choose a three-digit number so that decomposing two different units is a good strategy for finding the value of
$637 -$ . Explain your reasoning and find the value of the difference.