Look at the pattern of squares of numbers made only of 1s:
$1 1^{2} = 12111 1^{2} = 12321111 1^{2} = 1234321$
Following this pattern, what is $1111 1^{2}$ ?

Question

Look at the pattern of squares of numbers made only of 1s: 11^2 = 121 111^2 = 12321 1111^2 = 1234321 Following this pattern, what is 11111^2?

Accepted Answer

123454321. The square of a number with k ones (k <= 9) reads up to k then back down. For 11111 (5 ones): 123454321.

Step-by-Step Solution