This Problem Set is part of the the Lesson 10, Unit 2, Grade 5. In #3, Carmella estimated that she had 3,000 cards. Would rounding the number of boxes of cards to 20 have been a better choice? Is there a number between 10 and 20 that would have been a better choice for Carmella? Can you identify a situation in the real world where underestimating would be most appropriate?