Question

When a number is with 0, its square ends with how many zeroes

Answer 1

double the number of zeros it have .

Answer 2

HEY MATE! HERE'S UR ANSWER.

If an no. has one '0' at the end then the sq. of that no. ends with double of the zeros.
For Ex. (10)^2 = 100, (20)^2 = 400

I HOPE THIS HELPS.......☺️
#YASH