A square contains 23 blue, 12 red and 17 yellow beans. If I choose one bean from the box at random, what's the probability of it being blue?

First you need to add all the beans together.

23 + 12 + 17 = 52

So the square contains a total of 52 beans. 23 of those beans are blue.

So 23/52 is the probability of a random chosen bean being blue.