Brayden has 38 bags.
After giving away 15 bags of marbles, Brayden is left with 23 bags.
To find out how many bags he has we do 342 divided by 9 which is 38.
To find out how many marbles are in 15 bags we do 15 x 9 which is 135.
We then do 342 - 135 to find out how many marbles he has left which is 207 and divide 207 by 9 to convert that into bags, which is 23.
