Hi Jacob,

Since order is not important I am going to write a three digit combination by first choosing an item from the first pool, then an item from the second pool and lastly an item from the third pool. There are three items in the first pool so I have 3 possibilities in choosing an item from the first pool. There are two items in the second pool so no matter which item I chose from the first pool I have 2 possibilities for choosing an item from the second pool. Hence I have $3 \times 2$ possible choices for an item from the first pool and an item from the second pool.

In a similar fashion regardless of which of the $3 \times 2$ choices you have made from pools one and two you have four choices for an item from the third pool. Hence there are $3 \times 2 \times 4$ possible combinations from the three pools.

I hope this helps,
Penny