The 6^th triangular number is:

If a number ends in 5 zeros, its square ends in:

Which could be the remainder among the following when a per feet square is divided by 8?

Consider all integers from –10 to 5, and square each of them. How many distinct numbers do you get?

Write the digit in unit’s place when the following number are squared:

4, 5, 9, 24, 17, 76, 34, 52, 33, 2319, 18, 3458, 3453.