Combinatorics problems (each one builds on the previous one):
- If there’s a sequence of tasks you need to do, and you know how many ways there are to do each task, how many ways are there to do the whole sequence?
- How many ways are there to rearrange the letters of a word?
- Pick a spot on a grid. How many ways are there to go from the top-left to the spot using only steps to the right and steps down?
- This leads to Pascal’s triangle, which has all sorts of patterns.
- Here’s a weird one of those patterns: if you raise 11 to some power
n
, the answer will match then
th row of Pascal’s triangle! Why is this?





Simon got this from James Tanton’s course on Permutations and Combinations on GDaymath.com: https://gdaymath.com/courses/permutations-and-combinations/