Chapter 7  Lesson 7-4  Page 402
Key Idea Thinking about benchmark fractions can help you estimate fractional amounts.   Estimating Fractional Amounts   Vocabulary • benchmark   fractions   How can you estimate fractional amounts?   A fifth-grade class is making book shelves. The first board shown below is a whole board. Another board has been cut. About what fraction of the cut board is left?   Think about benchmark fractions. Benchmark fractions   include   and A length representing the whole   board could be cut into 2, 3, or 4 equal pieces to represent these benchmark fractions.  about About of the board is left.   About what fraction of the   shelf is painted?   About what fraction of the pie   has been eaten?   About of the shelf is   painted.   About of the pie has been   eaten. Talk About It 1. What is the benchmark fraction in Example A? Example B? 2. Draw a rectangle and shade about of it.