Timmy has 180 marbles, some plain and some colored. if there are 32 more plain marbles than colored marbles, how many colored marbles does he have

Well, we do not know how many colored marbles they are, so let's represent it with y. 
  The question says that there are 32 more plain marbles than colored. That can be represented as 32 + y
  The total number of marbles is 180. So that will be;
32+y=180
  subtract 32 from 180;
y=180-32
y=148
  So there are 148 colored marbles. Hope i helped. Have a nice day.