Dividing by 2

Dividing by 2 or halving is another important skill that must be mastered together with doubling.

The easiest numbers to halve are those composed entirely by even digits. Here we can perform halving digit by digit starting from the left.

Examples:

246 ÷ 2 = 123

8426 ÷ 2 = 4213

406,284 ÷ 2 = 203,142

Numbers ending in zeroes are also easy to halve.

50 ÷ 2 = (40 + 10) ÷ 2 = 20 + 5 = 25

700 ÷ 2 = (600 + 100) ÷ 2 = 300 + 50 = 350

1630 ÷ 2 = 815

Odd numbers are often combined with succeeding even numbers to simplify halving.

36 ÷ 2 = (20 + 10 + 6) ÷ 2 = 10 + 5 + 3 = 18

or (20 + 16) ÷ 2 = 10 + 8 = 18

or ( 30 + 6) ÷ 2 = 15 + 3 = 18

512 ÷ 2 = (400 + 100 + 12) ÷ 2 = 200 + 50 + 6 = 256

or (500 + 12) ÷ 2 = 250 + 6 = 256

Number splitting is very useful in halving.

367, 814 ÷ 2

= 36 | 78 | 14 ÷ 2

= 18 | 39 |07 = 183,907

754, 392 ÷ 2

= 754| 392 ÷ 2

= (600 + 140 + 14) | (200 + 180 + 12) ÷ 2

= (300 + 70 +7) | (100 + 90 + 6 )

= 377, 196

Try halving these numbers: