Find 51* 49 USING MENTAL MATH'

Question

asked Nov 12, 2018 91.7k views

2 Answers

Matthew Blackford · Answer 1 · 2018-11-16T11:56:32+0000

Answer:

The value of given expression is 2499.

Explanation:

The given expression is

$51\cdot 49$

This expression can be written as

$(50+1)\cdot (50-1)$

Using the property of algebraic expression we get

$(50+1)\cdot (50-1)=(50)^2-1^2$
$[\because (a-b)(a+b)=a^2-b^2]$

$(50+1)\cdot (50-1)=2500-1$

$(50+1)\cdot (50-1)=2499$

Therefore the value of given expression is 2499.