If he has 1,356 cards and each page he has holds 9 cards, we don't know how many pages he has, so that will be x
1,356/9x -----1,356 (# of cards) divided by 9 (cards each page holds) times x (# of pages)
Divide 9x by 9 to get x by itself -----9x/9=x
Then, what you do to one side you must do to another so divide 1,356 by 9 -----1,356/9=150.667
He needs 150 pages and has .667 left over.