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Question

The question -

An integer n has a square whose tens digit is odd. Find the units digit of n^2

what is the answer and how do you do it?

Answer 1

squares are 16,25,36.49,64.81
4^2 = 16 works. Its tens digit is 1 which is odd and its units digit is 6
6 also works its 10s digit is 3 which is odd and its units digit is also 6