Solution:

The class has 8 children. The first child shakes hands with the other 7 children. The second child has already shaken hands with the first child, and so has to shake hands with only the other 6 children. In this manner, the second-last child has to shake hands with only one child, and the last child has already met all the children. Thus, the number of handshakes is

7 + 6 + ........ + 2 + 1 = 28.

If there were 8 children in the class, then there were 28 total handshakes.

Food for thought:

It is obviously assumed that each child shakes hands with every other child once and only once.

More importantly, is there a quick way to add
7 + 6 + ........ + 2 + 1 ?
Indeed, there is! It simply equals 7 × 8 / 2. Can you show why such a formula holds? Click here to find out more.