Zachary did w push-ups and x crunches in gym class today. David did y more push-ups but z less crunches than zachary. How many more crunches than push-ups did Zachary do?
Zachary did 46 push-ups and 58 crunches in gym class today. David did 38 more push-ups but 62 less crunches than Zachary. How many more crunches than push-ups did Zachary do?

The answer is 12.