Question

A perfect square ends with the same two digits. How many possible values of this digit are there?

Answer 1

Answer:

A perfect square is a whole number that is the square of another whole number.

n*n = N

where n and N are whole numbers.

Now, "a perfect square ends with the same two digits".

This can be really trivial.

For example, if we take the number 10, and we square it, we will have:

10*10 = 100

The last two digits of 100 are zeros, so it ends with the same two digits.

Now, if now we take:

100*100 = 10,000

10,000 is also a perfect square, and the two last digits are zeros again.

So we can see a pattern here, we can go forever with this:

1,000^2 = 1,000,000

10,000^2 = 100,000,000

etc...

So we can find infinite perfect squares that end with the same two digits.