# Combinations

4 videos

2 skills

You are already familiar with calculating permutation ("How many ways could 7 different people sit in 4 different seats?"). But what if you didn't care about which seat they sat in? What if you just cared about which 4 people were in the car? Or put another way, you want to know how many combinations of 4 people can you stick in the car from a pool of 7 candidates. Or how many ways are there to choose 4 things from a pool of 7? Look no further than this tutorial to answer your questions.

### Handshaking combinations

VIDEO
7:29 minutes

Sal figures out how different combinations of people can shake hands.

### Combination example: 9 card hands

VIDEO
7:42 minutes

Thinking about how many ways we can construct a hand of 9 cards

### Combinations

PRACTICE PROBLEMS

Introductory combination problems like if you have 5 friends and can pick 2 of them to join you on a boat ride, how many different groups of friends could you take with you?