Multiply by 5, 25, or 125

To multiply by 5:

  1. Multiply the number by 10
  2. Then divide the result by 2
48 × 5
48 × 10 = 480
(multiply by 10)

480 ÷ 2 = 240
(divide by 2)

To multiply by 25:

  1. Multiply the number by 100
  2. Then divide the result by 4
32 × 25
32 × 100 = 3200
(multiply by 100)

3200 ÷ 4 = 800
(divide by 4)

To multiply by 125:

  1. Multiply the number by 1000
  2. Then divide the result by 8
24 × 125
24 × 1000 = 24000
(multiply by 1000)

24000 ÷ 8 = 3000
(divide by 8)

Notice that sometimes it is easier to flip the order, that is divide first then multiply