This brain bender is going to go in stages -- each getting harder than the last... See how far you can go!

Stage 1:

If you have TWO people in a room and each person shakes hands with every other person exactly once, how many total handshakes happen? Solution >

Stage 2:

If you have THREE people in a room and each person shakes hands with every other person exactly once, how many total handshakes happen? Solution >

Stage 3:

If you have FOUR people in a room and each person shakes hands with every other person exactly once, how many total handshakes happen?Solution >

Stage 4:

If you have FIVE people in a room and each person shakes hands with every other person exactly once, how many total handshakes happen? Solution >

Stage 5:

So, if you have SIX people in a room and each person shakes hands with every other person exactly once, how many total handshakes happen? SEVEN people?

EIGHT people? Solution >

EIGHT people? Solution >