100 is the square of the integer 10. Here are four increasingly difficult questions involving squares adding up to 100.

1. Express 100 as the sum of the squares of two different integers.
2. Now express 100 as the sum of the squares of five different integers.
3. Express 100 as the sum of the squares of three different integers.
4. Finally, express 100 as the sum of the squares of four different integers.