A method of representing permutations through using a diagram of possible choices.
Resembles a real life tree.
Each decision is a node, each final node is a branch.
Counting branches with Multiplicative Counting Principle
The more options you have in a tree diagram, the more complex it is to count. You dont need to count each branch if your tree is a regular tree with each branch at same hierarchy, you can do simple multiplication
Example
For example, the problem may be making a sandwich: Meat choices: Ham, Pastrami, Salami, Turkey Bread choices: Plain, Whole-wheat, Rye Lettuce: Iceberg, Greenleaf Sauces: Dill, Barbeque, Mustard There are 4 meat choices, 3 bread, 2 lettuce, 3 sauces. to get all options: multiply each # of options with each next # of options. 4*3*2*3 = 72 72 branches.