Rainbow Numbers – A missing number activity

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Introduce the concept of missing numbers to older toddlers or preschoolers with this simple activity that uses only three supplies! This activity is great for preschoolers and young school age kids to help strengthen their counting skills.

Here’s what you will need to get started.


Set up:

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Start off by writing the numbers on the circle stickers. If your Rainbow Building Blocks are like mine you can use the guide below to help you know which numbers to write.

Purple: 1 to 3; Dark Blue: 1 to 4; Light Blue: 1 to 5; Green: 1 to 6; Yellow: 1 to 7; Orange: 1 to 8; and Red: 1 to 9.

Stick the numbers onto the Rainbow Building Blocks skipping one number. I skipped the second last number. The more proficient your preschooler is with numbers the more numbers you can skip. However, if you introducing this concept to your preschooler for the first time only remove one number.

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Start by counting the numbers on the first Rainbow Building Blocks and then ask your preschooler when you get to 2,  “Oh wait, where’s the 2?”. Hand her the missing number stickers and ask her to put the missing 2 where is belongs on the Rainbow Building Blocks.

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Continue doing this for the next few blocks until she gets the hang of it. This was the first time that I introduced the concept of missing numbers to my toddler/preschooler so we counted each Rainbow Building Blocks together. Each time we got to the missing number I asked her “Oh wait, where’s the __?”.

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She got the hang of it by the end but still enjoyed my total shock when I could not find the missing number.

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So yes the Rainbow Building Blocks are likely to fall when your preschooler tries to put the numbers on them, especially the larger they get. This ended up being the most enjoyable part of the activity for my toddler/preschooler.

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She loved seeing them fall down like dominoes. Counting took a back seat for a little bit while she made them fall on purpose.


Not only is this activity great for counting, it also is great for those all important fine motor skills (and cause and effect!)!

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