Question

Find 51* 49 USING MENTAL MATH'

Answer 1

I used mental math and it took a long time, but I got the answer of 2,499.

Answer 2

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.