Your friends can influence you in ways you may not realize. They can influence the way you think and behave, your likes and dislikes, what you buy, how well you do in school. Information on who you know is useful to scientists because we can use it to better understand how ideas, or in some cases diseases, spread. Scientists and mathematicians can use data and advanced mathematics to make educated guesses about how likely something is to occur. For example, we can predict your likelihood of being friends with another person given just a few pieces of information, like what school you attend, your hobbies, and who you know! In this article, you will learn about some of the tools to become a network scientist and make your own mathematical predictions about friendships!