Multiplication

Strategies

100

Strategy for 1x a number

The number stays the same

200

Strategy for 3x a number

Double the number then add one more of the number

300

Strategy for 10x a number

Move the decimal one place to the right

400

Strategy for 9x a number

10x a number then minus the number

500

Strategy for 7x8

Square 7 plus 7 or square 8 minus 8

Strategies 2

100

Strategy for 2x a number

Double the number

200

Strategy for 4x a number

Double the number and then double it again

300

Strategy for 5x a number

10x the number then divide by 2 (halve)

400

Strategy for 11x a number

10x a number then add the number

500

Both strategies for 12x a number

10x plus 2x or 11x plus the number

Examples

100

How would you solve 3x6

(2x6)+6

200

How would you solve 4x8

(2x8)x2 or (2x8)+(2x8)

300

How would you solve 10x2.5

Move the decimal from after the 2 to after the 5

400

How would you solve 9x7

(10x7)-7

500

How would you solve 5x9

(10x9)/2

Solve

100

What is 3x6?

18

200

What is 4x9?

36

300

What is 6x7?

42

400

What is 12x11?

132

500

What is 6x8?

48

Division

100

Is 643 divisible by 2?

No

200

Is 195 divisible by 5?

Yes

300

What multiplication question would you use to help you solve 10/2?

5x2 or 2x5

400

Is 230/9 going to be larger or smaller than 23?

Larger

500

How can multiplication help you solve a division question?

You can turn it around and think "what time the divisor equals the dividend?"