Composing and Decomposing Numbers

A group of girls worked on ways to represent the number seven, using stones. I asked them how they could make 7 using green and brown stones. The girls got to work quickly.

Drawing her representation of 7

Using classroom resources to support writing the numbers 

I.L made 7 using 4 green and 3 brown. Together, we wrote the math sentence 4+3=7.

D.M made 7 using 1 green and 6 brown.

A.H made 7 using 3 brown and 4 green.

These girls are demonstrating the skill 'composing and decomposing numbers'. This means the ability to build and take apart numbers.

This skill can be taught in many different ways and naturally throughout your day. Here are a few examples of ways you can get your child to think about numbers being broken apart and put together.

• I have 8 socks. Some are blue and some are pink. What socks could I have? (You could challenge your child to see how many ways they could do this)
• Nine grapes were in my bowl. I ate 3 grapes. How many grapes are in my bowl now?
• Six crayons are in the box. Two are red and the rest are blue. How many blue crayons are in the box?

We use many different manipulatives to help the students build this skill, here are a few. 

• 10 frames and 5 frames with different coloured counters

Showing 5 with 3 white and 2 red 

• Snap cubes

Making 5

• Beads

  

  Using pipe cleaners and beads to show the different ways to make 3
  (Click the picture to link to another blog with games for this math concept)

This is an important skill for the students to gain a foundational knowledge and understanding of numbers. We are excited to continue to watch them learn and explore this concept of composing and decomposing numbers.