Mixture of problem

Last week I was learning about Mixture of problems. For example Miss Berry
has a loille jar which has 502 lollies in it. If Miss berry gives out 217 lollies to her
student, how many lollies would see have left in the jar? A way I would do this is
 502 - 200 = 302. then 302 - 10 = 292. Then 292 - 7 = 285 .By solving this
problem I used partitioning . How would you solve this question?