Lesson 7 Compose a Larger Unit

    • Let’s add three-digit numbers and compose tens or hundreds.

Warm-up How Many Do You See: Are They the Same?

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

  1. Base ten diagram. 3 hundreds, 5 tens, 3 ones.
  2. Base ten diagram. 3 hundreds, 4 tens, 13 ones.
  3. Base ten diagram. 2 hundreds, 15 tens, 3 ones.

Activity 1 Compose a Ten or a Hundred

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

  3. Compare your thinking with your partner.

Activity 2 Walk About and Add

Problem 1

Directions:

  • Find a partner and record your numbers to make an expression.

  • Discuss if you think you would need to compose a ten or a hundred when adding your numbers.

  • Find the value of the sum. Show your thinking.

  1. +

  2. Will you need to compose a ten? Yes or No

  3. Will you need to compose a hundred? Yes or No

  4. Find the value of the sum. Show your thinking.

Problem 2

  1. +

  2. Will you need to compose a ten? Yes or No.

  3. Will you need to compose a hundred? Yes or No.

  4. Find the value of the sum. Show your thinking.

Problem 3

  1. +

  2. Will you need to compose a ten? Yes or No

  3. Will you need to compose a hundred? Yes or No

  4. Find the value of the sum. Show your thinking.

Practice Problem

Problem 1

Find the value of each sum. Explain your reasoning.