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Making “Required” Math Easy: Composing and Decomposing Numbers

2013-07-15 by Zina Harrington

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Our family game closet is chock-full and diverse. We’ve got board games, DVD games, interactive games, dice, spinners, cards, pegs… You name it, we’ve likely got it. Each of us certainly has their favorite, but there’s one game that gets considerably more use than all the others.

Sometimes simple is best. Our family loves the classic game of Shut-the-Box.

make decomposing numbers easy playing game 1

Shut-the-Box serves two very important functions:

  1. It makes math enjoyable for children & parents alike.
    Stop by my house and you’ll find it laying around somewhere in the kitchen or living room. I play and chat with the girls while prepping dinner. We use it during family game night. It’s my go-to-game for a coffee date with my daughters Rose & Quinn. It’s portable, quiet, and perfect for playing solo or with someone else.
  2. It teaches your child to compose & decompose numbers.
    In many school districts, this is a core requirement for early elementary students. Shut-the-Box can help children with this skill at multiple levels.

Learn what “composing & decomposing numbers” means for your child below. I’ve broken the skill down for Pre-Kindergarteners and Early Elementary students.


What “composing & decomposing numbers” basically means is that your child understands that numbers can be created in multiple ways. For example, the sum of 10 can be reached with the following equations: 9+1, 3+7, 6+4, and so on. This concept provides your child a sound foundation for later mathematical operations, like addition, subtraction, multiplication, and division. With each turn of Shut-the-Box, your child practices composing & decomposing numbers.

  • Composing
    Every time your child rolls the dice, they practice composing numbers. After a few games, they quickly learn that 4+3, 5+2, and 1+6 all equal 7.
  • Decomposing
    Once they tally the dice, children decompose the number within the box. So for example, if your child rolls a 2+5 , they might still decide to decompose the 7 to 1+6 on the game board.


Early Elementary Children

Through basic dice games, your child likely naturally understands how to compose & decompose numbers within ten. Working repetitively with materials preps a child for a smooth transition to more abstract thinking. Your child is now ready to expand on their learning and understand place values when composing & decomposing larger numbers. Below is a visual of how to compose & decompose numbers into units.

making decomposing numbers easy chart

Having your child add together a set amount of Shut-the-Box scores is a great way to have them practice composing & decomposing numbers. For example, if your child had a current score of 136 and just finished a turn scoring 12, you’d have them solve the equation by adding the units of hundreds (1), tens (40) and ones (8) for a total of 148. If your child needs assistance, ask:

  • How many hundreds are there?
  • How many tens are there?
  • How many ones are there?

Our family usually competes over a game of 10 turns. Click here for a
FREE PRINTABLE (PDF) for keeping score!

A little bit of friendly competition will have your child asking for a re-match. (Yes, asking to do more math!) Over time, practicing these basic skill sets will prepare your child for the abstract world of algebra.

Long-term, it’s important that your child not just memorize but also understandnumbers relationally. Shut-the-Box is a great way to build up a strong math foundation.

Any questions? Let’s chat in the comments.

Looking for additional information?

Check out these five great Pinterest boards on the topic:

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Zina Harrington

Zina is the author of Let’s Lasso the Moon and Becoming UnBusy, where she inspires parents and children to interact creatively and enjoy the beauty of everyday moments. Facebook | Pinterest | Blog | Instagram

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