## Basic College Mathematics (9th Edition)

estimate - 17 exact - 17$\frac{1}{12}$
31$\frac{3}{4}$ - 14$\frac{2}{3}$ Estimate : 31$\frac{3}{4}$ round to 32 14$\frac{2}{3}$ round to 15 So subtract 32 – 15 = 17 is the estimate answer Exact : 31$\frac{3}{4}$ - 14$\frac{2}{3}$ The least common multiple of 4 and 3 is 12. Rewrite all the fractions as fractions with a least common denominator of 12 Rewrite as like fraction 31$\frac{3}{4}$ - 14$\frac{2}{3}$ = 31$\frac{9}{12}$ - 14$\frac{8}{12}$ Subtract : 31$\frac{9}{12}$ - 14$\frac{8}{12}$ Subtraction of the whole number is 17 and Subtraction of the fraction is $\frac{1}{12}$ = 17$\frac{1}{12}$ The estimate was 17, so the exact answer of 17$\frac{1}{12}$is reasonable