How_To_Be_Good_At_Math

CALCULATING • THE MULTIPLICATION GRID CALCULATING • MULTIPLICATION PATTERNS AND STRATEGIES 107

Multiplication patterns

and strategies

There are lots of patterns and simple strategies that will help you to

learn your multiplication tables and even go beyond them. Some of

the easiest to remember are shown in the table on this page.

×2

To multiply How to do it Examples

×9

×11

×12

Double the number – that is, add it to itself.

Multiply the number by 10, then subtract the

number.

To multiply the numbers 1 to 9 by 11, write the

digit twice, once in the tens place and once in

the ones place.

Multiply the original number by 10, then multiply

it by 2, then add the two answers.

For calculations up to 9 × 10, you can use a

method that involves counting your fingers.

2 × 11 = 11 + 11 = 22

×4

Double the number, then double again. 8 × 4 = 32, because double 8 is 16 and

double 16 is 32.

9 × 7 = (10 × 7 ) − 7 = 63

To work out 3 × 9, hold your hands up

with your palms facing you. Then hold

down your third finger from the left.

There are 2 fingers to its left and 7 to

its right, so the answer is 27.

4 × 11 = 44

12 × 3 = (10 × 3 ) + (2 × 3 ) = 30 + 6 = 36

×5

The ones digit of multiples of 5 follow the

pattern 5, 0, 5, 0 ...

Multiply by 10 then halve the result.

The first four answers in the 5× table are

5 , 10 , 15 , and 20.

16 × 5 = 80, because 16 × 10 = 160, then

halve 160 to make 80.

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