Q. Find the squares of the following numbers containing 5 in unit’s place.
(ii) 95
Assume a number with unit digit 5 = a5
= = 10a(10a + 5) + 5(10a + 5) = 100a 2 + 50a + 50a + 25
= 100a(a + 1) + 25
= a(a + 1) hundred + 25
We are going to use this result here.
In this question a = 9
so, = 9(9+1)hundred + 25
= 9000 + 25 = 9025