Basic College Mathematics (10th Edition)

Published by Pearson
ISBN 10:
ISBN 13:

Chapter 3 - Adding and Subtracting Fractions - 3.4 Adding and Subtracting Mixed Numbers - 3.4 Exercises - Page 228: 26

Answer

Estimated answer = 6 Exact answer = $6\frac{17}{20}$

Work Step by Step

$11\frac{9}{20}$ - $4\frac{3}{5}$ Estimation: $11\frac{9}{20} \approx 11$ $4\frac{3}{5} \approx 5$ Therefore $11\frac{9}{20}$ - $4\frac{3}{5}$ $\approx$ 11 - 5 = 6 Exact Calculation: $11\frac{9}{20}$ - $4\frac{3}{5}$ = $11\frac{9}{20}$ - $4\frac{3\times4}{5\times4}$ (20 is the least common denominator) = $11\frac{9}{20}$ - $4\frac{12}{20}$ = $11$ + $\frac{9}{20}$ - ($4$ + $\frac{12}{20})$ = $11$ + $\frac{9}{20}$ - $4$ - $\frac{12}{20}$ = ($11$ - $4$) + ($\frac{9}{20}$ - $\frac{12}{20}$) (Solving whole parts separately and fractional parts separately) = $7$ + $\frac{9 - 12}{20}$ = $7$ + $\frac{-3}{20}$ = $6+1$ - $\frac{3}{20}$ = $6$ + $\frac{20}{20}$ - $\frac{3}{20}$ = $6$ + $\frac{20 - 3}{20}$ = $6$ + $\frac{17}{20}$ = $6\frac{17}{20}$ The estimate was 6, so the exact answer of $6\frac{17}{20}$ is reasonable.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.