## Basic College Mathematics (9th Edition)

Estimate: 17 Exact: $17\frac{1}{6}$
To estimate, we round the fractions to the nearest whole number: Estimate=$22-5=17$ Next, we find the exact answer: Exact=$21\frac{6}{6}-4\frac{5}{6}=(21-4)+(\frac{6}{6}-\frac{5}{6})=(17)+(\frac{1}{6})=17\frac{1}{6}$ Which is close to the estimate.