Colton had 72 dolphin stickers. He gave 4 stickers each to 3 friends. He also gave his friend Mandy 2 more than he gave his three friends total.  And he gave Justin 10 less than Mandy. How many stickers does Colton have left? Let's answer step by step:
Colton gave away 4 stickers * 3 friends = 12 stickers. Colton gave Mandy 2 + 12 stickers = 14 stickers. Colton gave Justin 14 stickers - 10 = 4 stickers. In total, Colton gave away 12 + 14 + 4 stickers = 30 stickers. Colton's number of total stickers at the end is 72 - 30 = 42 stickers. The answer: 42.