Decomposing and composing 1,000

General

Students practice decomposing and composing 1,000 with ones, tens, and hundreds.

Relevance

It is useful to be able to decompose and compose 1,000 so you know how much is left of a number. If you're saving to buy something, you want to know how much more you need before you reach your goal.

Introduction

Students count by turns in pairs to 1,000 in different ways. They can skip count in 10s, 50s and 100s.

Development

Explain the number values of the MAB blocks and ask students to compose 350 by dragging the blocks to the box on the right. Show with the example how to compose 1,000 with hundreds and ask them to also practice dragging the blocks. Tell students that you can easily compose 1,000 if you know how to compose 100. The students see the number bond chart of 1,000 with the number bond chart of 100 next to it as a support. Explain how you can easily compose 1,000 with tens and hundreds and ask students to also practice this. Show how you can also count this with jumps on the number line. Explain step by step how you can use MAB blocks to compose 1,000 from any random number. First you count on ones, then tens, then hundreds and count on to 1,000. Also show this process on the number line. Finally students are asked to decompose 1,000. They are asked to decompose in their heads.

Check that students understand decomposing and composing 1,000 by asking the following questions:
- What can you use as support to compose 1,000? (MAB blocks or the number line)
- Can you explain how to compose 1,000 from 547?

Guided Practice

Students first practice composing 1,000 by completing the number bond chart and then also do decompositions of 1,000 without visual support.

Closing

Students complete three number bond charts of 1,000. Point out that they can compose numbers in their heads imagining the MAB blocks. Discuss why it is useful to be able to decompose and compose 1,000. An example is if you want to know how much money you have saved of your goal of 1,000 dollars.

Teaching Tip

Students who have difficulties decomposing and composing 1,000 can use the MAB blocks as support for composing and decomposing the numbers. They can also draw the jumps on a number line.