Basic College Mathematics (10th Edition)

$21\frac{1}{8}-20\frac{1}{4}=21.125-20.25=0.875=\frac{7}{8}$ inches
To change the fractions to decimals, first we need to write $\frac{1}{8}$ and $\frac{1}{4}$ as decimals. We do this by dividing: $~~~~0.125$ $8\overline{)1.000}$ $~~~~~~~\underline{8}$ $~~~~~~~20$ $~~~~~~~\underline{16}$ $~~~~~~~~~~40$ $~~~~~~~~~~\underline{40}$ $~~~~~~~~~~~~~0$ $~~~~0.25$ $4\overline{)1.00}$ $~~~~~~~\underline{8}$ $~~~~~~~~20$ $~~~~~~~~\underline{20}$ $~~~~~~~~~~~0$ Therefore, $21\frac{1}{8}=21.125$ and $20\frac{1}{4}=20.25$. We find the difference: $21.125-20.25=0.875$ inches We convert this to a fraction: $0.875=\frac{875}{1000}=\frac{7}{8}$ This matches our answer to Exercise 34. We see that the fraction and decimal methods yielded equivalent answers, although it was simpler to work in fractions.