Combinatorial proof

A combinatorial proof is when you use numbers and grouping to show why something is true. It helps us understand why it's true by counting different possibilities or configurations. For example, if you wanted to prove that every time you flip a coin, you have a 50% chance of getting heads, you could make two groups, a heads group and a tails group, and then count how many ways you can get either. Since there are only two choices when you flip a coin, the number of heads possibilities will be the same as the number of tails possibilities, so the probability of getting heads is 50%.