zaachary had ten more super hero stickers than Andrew, so he gave Andrew half of his stickers. Then Andrew had more stickers than Zachary, so he gave Zachary four stickers. Then they both had thirteen stickers. How many stickers did each boy have originally?

Originally, Zachary had 18 stickers and Andrew had 8.

You can do this by working backwards. Subtract 4 from Zachary's end total of 13 and add 4 to Andrew's 13 because Andrew gave Zachary 4. That leaves Zachary with 9 and Andrew with 17. Since this would be after Zachary gave Andrew half his stickers, you know that 9 is half of Zachary's original amount. So add 9 to Zachary's to get 18 and subtract 9 from Andrew's 17 to get 8.