Question

If square of 11 is 121 then, what is the square of 111?

(a) 121

(b) 12321

(c) 1234321

(d) 123321

The question was posed to me in an international level competition.

This key question is from Properties of Squares topic in section Squares and Square Roots of Mathematics – Class 8

Answer 1

The correct answer is (b) 12321

The explanation is: The squares of the numbers containing one on all places show a very beautiful pattern.

The pattern is as follows, 11^2=121 => 111^2=12321. Hence students can use this pattern to calculate the squares of all the numbers having 1 on it’s all places.