Answer:
Mr. Toshio started with 32 rulers
Step-by-step explanation:
Let x be the number of rulers he start with
Mr. Toshio lent out 11 rulers at the beginning of class
Number of rulers - 11

He collected 4 rulers in the middle of class. So we add 4

He gave out 7 at the end of class. So we subtract 7

He had 18 at the end of the day.


Add 14 on both sides

Mr. Toshio started with 32 rulers