Multiply two digit numbers having same tens digit and ones digits add up to 10
38 x 32 = 1216
Step 1 – Multiply the first digit by the first digit plus one:
3 x (3 + 1) = 12
Step 2 – Multiply the rightmost digits (if the result is a single digit put a 0 in front of it):
8 x 2 = 16
Step 3 – Put the result from step 2 next to the result from step 1:
Trick 2
Square numbers if you know the square of the previous number
61 x 61 = 3721
Step 1 – Find the square of the previous number:
60 x 60 = 3600
Step 2 – Multiply the number being squared by two and subtract one:
(61 x 2) – 1 = 121
Step 3 – Add step 2 to step 1: 3600 + 121 = 3721
Trick 3
Multiply between 10 and 19
18 x 17 = 306
Step 1 – Add the larger number to the rightmost digit of the other number:
18 + 7 = 25
Step 2 – Put a 0 at the end of the result from step 1: 250
Step 3 – Multiply the rightmost digits of both original numbers: 8 x 7 = 56
Step 4 – Add steps 2 and 3: 250 + 56 = 306
Trick 4
Multiply two digit number by 11
53 X 11 = 583
Step 1 – Add both digits of the two digit number:
5 + 3 = 8
Step 2 – Place the result in between both digits: