Building with colours
The missing manipulative: build numbers from their prime factors, right in your browser.
Before this, try: Building with rows and columns
You need: A phone, tablet or computer. No cards needed.
Players: 1 or more
Goal: Find the number that a set of colours makes.
Steps
- Tap a colour to drop it onto the board.
- Guess the number the colours make on the 100 square.
- Tap a disk to take it out, and try another number.
- Every 10 numbers you find unlocks a new colour.
Why colours?
We start building numbers with counters and ten frames. Place value has Dienes blocks. Times tables have rows and columns. But when we want children to think multiplicatively (factors, multiples, fractions, ratio), the manipulative is missing.
Prime Colours fills that gap: every number is built from coloured disks, one colour for each prime factor. Start here to get a feel for it before you pick up the cards.
- Which numbers can't be built?
- Which numbers use only one colour?
- What happens to the number when you add the same colour again?
Get the cards
Every activity here uses a Prime Colours pack. The shop is reopening soon; email to order a pack now.
Staff training & parent workshops
Bring Prime Colours to your school: hands-on sessions for teachers and families.
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