A tree has roots, branches and leaves, giving people a forked feeling. In mathematics, with the help of the tree diagram constructed by the bifurcation characteristics of trees, various conclusions that may appear in mathematical problems can often be judged one by one.
"Tree diagram" is one of the most widely used figures in mathematics.
In mathematical counting problems, whenever we are faced with some unconventional problems, enumeration method can often exert great power. Enumeration is also called exhaustive method. As the name implies, it is to list all the objects that meet the requirements of the topic one by one, and then select the reasonable ones according to the requirements.
However, how to enumerate all eligible objects without repetition or omission in the enumeration process?
"Tree diagram" can make our enumeration process not only intuitive, but also organized, not easy to repeat or omit, so that people can see at a glance.