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ELI5 Yahaaa

Counting without counting

Why Are Rows and Columns Useful?

Arrange things in a grid and you can find the total without counting one by one.

Scattered You must count everyoneIn a grid Rows times columnsgives the total
Arrangement turns counting into multiplication.
  1. Step 1 of 5

    Scattered things are slow to count.

    Twelve so far……and twelve more, if youkeep track

    A pile of twenty-four counters takes twenty-four steps and it is easy to double-count or miss one.

  2. Step 2 of 5

    A grid makes the structure visible.

    1 Scattered2 Arranged inrows3=4 rows × 6 = 24

    Line them into four rows of six. Now you can see the shape of the number, and count six four times instead of one twenty-four times.

  3. Step 3 of 5

    An array shows why order does not matter.

    4 rows of 6 24Turned: 6 rows of 4 Still 24

    Turn the grid a quarter turn and four rows of six become six rows of four. Same counters, so 4 × 6 must equal 6 × 4.

  4. Step 4 of 5

    It makes division obvious too.

    1 24 in 4 rows2?How long iseach row?3=6 — that is 24÷ 4

    Twenty-four shared between four is asking how long each row is. The same grid answers both multiplication and division questions.

  5. Step 5 of 5

    Grids are everywhere.

    1 Egg boxes2 Chocolatesquares3 Pixels on ascreen

    Egg boxes, chocolate bars, seats in a cinema, pixels on a screen, tiles on a floor. We arrange things in grids because it makes counting them easy.

    This is exactly why children are shown times tables as grids — the picture makes the fact make sense.

The short version

Arranging things in rows and columns replaces counting with multiplying, and shows why order does not matter.

Try it yourself

Look at a chocolate bar before breaking it. Count one row and one column, multiply, and you know the total.

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