1. X by 20 Can you remember how to x by 20? Lets try 25 x 20
First split 20 into two of it’s factors:
2 and 10
Multiply 25 x 2
= 50
Now multiply 50 x 10
That gives us 500

2. Shall we try it again
36 x 20
36 x 2
=72
72 x10
=720

3. Now what about x 40 Easy!!! Let’s split 4 into 2x2 Then we’ll x 10
So 17 x 40
17x2
=34
34x2=68
68x10
=680
Now try 23x 40 on your own.

4. How can we x by 19? Easy!!!!! Just x by 20 Then adjust, take one away.
Eh-I don’t understand (Louise!!)
Well lets do 15 x192
So 15 x 20 so
15 x2
=30 x10
=300
Then take away one lot of 15
300-15=285

5. Now try these
18 x 19
22 x19
33x19
35 x19
26 x 19
42 x19
47 x19
55 x19
Think you are clever-work out a quick way of x 21.
E.g 18 x 21
18 x20
=360
Then add another lot of 18
=378