← Methods
Multiply by 5
Five is half of ten. Halve the number and then times ten, or times ten and then halve — whichever keeps you in whole numbers.
When it works
Anything times 5.
Worked through
48 × 5 = 240
- 48 ÷ 2 = 24Five is half of ten, so halve it first.
- 24 × 10 = 240Then times ten.
10 problems, every one of them this method.