AC9MFN05 · FOUNDATION · NUMBER

Adding and Taking Away

Act out addition and subtraction, then count or subitise to find how many.

Once a child sees that a number is made of parts, addition and subtraction are the next, natural step. They are not new and separate tricks — they are simply what happens when groups change. Add, and a group grows. Take away, and it shrinks. At Foundation, this is best met not as written sums but as stories acted out with real things: counters, blocks, coins, fingers. The numbers come after the action, to say how many.

Addition is joining. Put a group of four counters beside a group of three, push them together, and ask how many there are now. The answer does not require a formula — a child can count them all, or, once the parts are small and familiar, simply see that four and three is seven. That instant recognition of small amounts, without counting one by one, is subitising, and it makes adding quick.

Subtraction is the opposite motion: taking some away. Start with seven counters, remove three, and count what is left. The same story can be told with anything — birds flying off a fence, biscuits eaten from a plate, coins spent at the tuckshop. The action is always “there were this many, some went, how many remain?”

As children grow more confident, they meet a faster way to add called counting on. Instead of counting a group of five all over again to add two, they hold “five” in their head and count on: six, seven. Starting from the larger group and counting on the smaller one saves effort, and it shows the child that they can trust a number they already know rather than recounting from one every time.

It helps to know where children commonly stumble, so you can watch for it. A very common one is recounting the whole group every time, even after a child clearly knows how many are in the first part — counting “one, two, three, four” again before going on, rather than starting from four. Another is losing track of which counters have already been taken away during subtraction, so the same one gets removed twice or skipped. Slowing the action down, and saying the running total aloud while pointing, turns a guess into reasoning a child can check.

The deepest idea in this unit is that addition and subtraction are linked. If four and three make seven, then seven take away three must leave four. The same three numbers — four, three, seven — make a little family of facts: 4 + 3, 3 + 4, 7 − 4, and 7 − 3. A child who sees this stops treating every sum as a fresh puzzle. Knowing one fact hands them three more for free, because they are all the same story told from different starting points.

None of this needs a worksheet to begin. Sharing snacks, counting toys into and out of a box, or working out how many are left after some are given away all build the same sense. The five visualisations below let a child act these stories out on the screen: join two groups, take some away, count on from the bigger group, see a fact family, and spend coins at the tuckshop. Each one returns to the same simple question — how many now?

See it five ways

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