Question

Question 1 (i)
What will be the unit digit of the squares of the following number:

81

Answer 1

We know that if a number has its unit digit as 'a'(say), then the unit digit of square of the number will always be the unit digit of $a^2$.
The number 81 contains its unit’s place digit 1. So, square of 1 is 1. Hence, unit’s digit of the square of 81 is 1.