Lesson 8 Compose Tens and Hundreds to Add

    • Let’s compose tens and hundreds to add.

Warm-up How Many Do You See: Too Many Tens

How many do you see? How do you see them?

  1. Base ten diagram. 2 hundreds, 7 tens, 8 ones.
  2. Base ten diagram. 3 hundreds, 7 tens, 10 ones.
  3. Base ten diagram. 3 hundreds, 12 tens, 6 ones.

Activity 1 Compare the Sums

Two students. One working with base ten blocks, the other writing 273 plus 81.

Find the value of each sum. Show your thinking. Use base-ten blocks if it helps.

  4. What was the same and different about the sums?

Activity 2 Different Ways to Show Your Thinking

  1. Priya and Lin were asked to find the value of .

    Priya’s work

    Base ten diagram.

    Lin’s work

    What do you notice about their work? What is the same and different about their representations? Be prepared to explain your thinking.

  2. Find the value of .

    Show your thinking. Use base-ten blocks if it helps.

Practice Problem

Problem 1

Find the value of each sum. Show your thinking.