# Multiplication Shortcut Part- 3

**Multiply a number by 0.5, 5, 50, or 500**

The general method for this group of multipliers is to divide the number by 2 and then multiply the multiplier by 2 (Doubling and Halving method)

For Example:

272 × 500 = (272/2) × (2 × 500) = 136 × 1000 = 136,000

If the number is odd, Just subtract 1 from the number and divide the number, and attach .5 then multiply.

89 → 88

88 × 50 = (88/2) × (2 ×50) = 44 attach .5 × 100 = 44.5 × 100 = 4450

**Multiply by 0.25, 2.5, 25, or 250**

The general method for this group of multipliers is to divide by the number 4 and then multiply the multiplier by 4. [If you multiply these multiplier 0.25, 2.5, 25, or 250 by 4, you will get 1, 10, 100, 1000 respectively].

For Example:

92 × 0.25 = (92/4) × (4 × 2.5) = 23 × 10 = 230

If the number to be multiplied is not evenly divisible by 4, there will be a remainder of .25, 0.5, or 0.75 but the same steps apply.

For Example:

22 × 2.5 = (22/4) × (4 × 2.5) = [(20 + 2)/4] × 10 = (5 + 0.5) × 10 = 55

**Multiply by .125, 1.25, 12.5, or 125**

First check the divisibility Rule for 8 that is if the last three-digit is divisible by 8 or if the integer is divisible by 2 three times then the number is divisible by 8. If the number is divisible by 8 then apply this method.

The general method for this group of multipliers is to divide by the number 8 and then multiply the multiplier by 8. [If you multiply these multiplier 0.125, 1.25, 12.5, or 125 by 8, you will get 1, 10, 100, 1000 respectively].

For Example:

128 × 1.25 = (128/8) × (8 × 1.25) = 16 × 10 = 160

360 × 125 = (360/8) × (8 × 125) = 45 × 1000 = 45,000

**Multiply by .75, 7.5, 75, or 750**

0.75, 7.5, 75, and 750 are not evenly divisible into 1, 10, 100, or 1,000 but we can easily convert it to easy multiplier such as .75, 7.5, 75, or 750 are equivalent to ¾, 30/4, 300/4, or 3000/4 respectively.

For Example:

128 × 7.5 = 128 × (30/4) = 32 × 3 × 10 = 960

256 × 75 = 256× (300/4) = 64 × 3 × 100 = 192 × 100 = 19,200