With this trick, you will be able to multiply any two numbers from 11 to 19 in your head quickly, without the use of a calculator. Just follow four simple steps.
I will assume that you know your multiplication table reasonably well up to 10x10.
Try this:
Take 14 x 18 for an example.
Add the first number to the last digit of the second number : 14 + 8 = 22
Multiply the result by 10: 22 x 10 =220
Multiply the last digits of both numbers together: 4 x 8 = 32
Add: 220 + 32 = 252
Another Example
Q. 11 x 14 = ?
Step 1: 11 + 4 = 15
Step 2: 15 x 10 = 150
Step 3: 1 x 4 = 4
Step 4: 150 + 4 = 154