Multiply in parts

Split a number into useful parts, then add the products.

Use a number you know

To work out 12 × 4, split 12 into 10 + 2. Multiply both parts by 4, then add them.

The picture keeps all four rows. Only the columns are split.

4 rows: 10 squares + 2 more in each row.

Multiply both parts, then add

12 × 4

= (10 × 4) + (2 × 4)

= 40 + 8

= 48

The smaller part is also multiplied by 4. Adding only 2 would leave out three of the four rows.

4 rows: 10 squares + 2 more in each row.

Try one more column

Now try 13 × 4. Split 13 into 10 + 3, multiply each part by 4, and add.

4 rows: 10 squares + 3 more in each row.

Try it

What is 13 × 4?

  1. 52
  2. 44
Show the answer

52

(10 × 4) + (3 × 4) = 40 + 12 = 52. You included all three extra columns in all four rows.

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