This Problem Set is a part of the Lesson 25, Unit 2, Grade 5. In this lesson, students begin to estimate quotients from decimal dividends and whole number divisors. They round the whole and the divisor using compatible numbers. For example, students solve 39.1 ÷ 17 and 3.91 ÷ 17 by rounding g to 40 ÷ 20 and 4 ÷ 2.