Billy likes the number 25 but not 35. He likes 144 but not 145. He likes 8100 but not 8000.
Does he like 872 or 841?
Billy likes the number 25 but not 35. He likes 144 but not 145. He likes 8100 but not 8000.
Does he like 872 or 841?
841
Because
he likes perfect squares.
$841 = 29^2$
he likes 25 because
$25 = 5^2$
He likes 144 because
$144 = 12^2$
He likes 8100 becasue
$8100 = 90^2$
That was easy. Billy likes
841.
Clearly because,
Billy likes perfect squares. 841 is the square of 29.