Section A: Practice Problems Add and Subtract Within 1,000 Without Composition or Decomposition

Section Summary

Details

In this section of the unit, we compared three-digit numbers and looked at how addition can be used to find the difference, especially when numbers are close together. We added and subtracted by counting on or back by place and used expanded form to think about adding or subtracting using place value based strategies.

Number line. Scale 120 to 200 by fives. Equally spaced tick marks. Frog jumps from a point between 180 and 185 to a point between 135 and 140.

Problem 1 (Pre-Unit)

Select all representations of the number 318.

$300 + 10 + 8$
$100 + 30 + 8$
Three hundred eighteen
Three hundred eighty-one

Problem 2 (Pre-Unit)

Write a number for each representation.

Five hundred twenty-seven
$300 + 60 + 8$
$5 + 40 + 700$

Problem 3 (Pre-Unit)

Find the value of each sum or difference. Show your thinking.

$52 - 43$
$65 - 19$
$36 + 47$

Problem 4 (Pre-Unit)

Find the value of each difference.

$77 - 10$
$77 - 20$
$90 - 70$

Problem 5 (Lesson 1)

Find the value of each difference. Show your thinking.

$53 - 50$
$285 - 281$
$90 - 88$

Problem 6 (Lesson 2)

Here are Kiran’s blocks.

Base ten diagram. 3 hundreds, 2 tens, 6 ones.

He gives 2 tens to Priya.
What is the value of Kiran’s blocks now? Show your thinking.
Then Priya gives Kiran 4 hundreds.
What is the value of Kiran’s blocks now? Show your thinking.

Problem 7 (Lesson 3)

Find the value of each difference. Show your thinking. Use a number line or base-ten blocks if it helps.

$648 - 25$
$535 - 24$

Problem 8 (Lesson 4)

Find the value of $600 - 289$ . Show your thinking.
Find the value of $245 + 612$ . Show your thinking.

Problem 9 (Lesson 5)

Find the value of each expression. Explain your reasoning.

$365 + 214$
$365 - 214$

Problem 10 (Exploration)

Here is Han’s work finding the value of a difference.

What difference did Han find? Show your reasoning.
Write an addition and a subtraction equation that match Han’s work.

Problem 11 (Exploration)

Tyler says he can find the value of $438 - 275$ using what he knows about differences of two-digit numbers.

“First I find $43 - 27$ and then I find $8 - 5$ and that gives me the answer.”

Use Tyler’s reasoning to find the value of $438 - 275$ .