
Tree diagrams are a method that can be used to solve counting problems. Trees begin at a root, then spreads to a number of branches from the root. Branches can the come out of previous branches. The ends of a Tree Diagram are called 'leaves.'
To help with counting problems, we use a branch to represent each possible choice. Leaves represent possible outcomes, and are defined as endpoints of a branch that do not have any other branches beginning at them. 