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

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

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.

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

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