Question

Find the squares of the following numbers:

(8) 105

Answer 1

The square of any number ending with 5 can be written as:
(a5)² = [a × (a + 1) × 100] + 25
Here, a is the number excluding the units digit.
So, the square of 105 can be calculated as:
[10 × (10 + 1) × 100] + 25
= [10 × 11 × 100] + 25
= 11000 + 25
= 11025