What is Monte Carlo?

Monte Carlo is like using lots of little guesses to find a big answer.

Imagine you're trying to figure out how many jellybeans are in a jar, but instead of counting them all at once, you drop in 100 little rubber balls and see where they land. Each ball gives you a clue about where the jellybeans might be hiding. After all the balls have landed, you use their positions to guess how many jellybeans there are total. That’s Monte Carlo, using many small guesses (or random samples) to solve a bigger problem.

You start with something you don’t know exactly, like the number of jellybeans in a jar or the chance of rain tomorrow. Then, instead of knowing everything at once, you make lots of random choices, like throwing balls into the jar. Each choice gives you some information. After many tries, you add up all your clues and get a good idea of what the real answer might be.

It’s like having a bunch of friends guess the number of jellybeans, each one picks randomly, and together they give you a much better guess than any single friend could.