Multiplication of two numbers that differ by 2

Maths Tricks , short cut tricks for maths to make calculation easy and fast

Multiplication of two numbers that differ by 2

(This trick only works if you have memorised or can quickly calculate the squares of numbers. When two numbers differ by 2, their product is always the square of the number in between these numbers minus 1.Let me explain this rule by taking examples
18*20 = 19^2 - 1 = 361 - 1 = 360
25*27 = 26^2 - 1 = 676 - 1 = 675

Example.

Understand the rule by 1 more example 49*51 = 50^2 - 1 = 2500 - 1 = 2499

Is this maths trick helpful?   (1260)   (412) Post / Read comment (0)