Answer
Estimated answer = 47
Exact answer = = $45\frac{5}{6}$
Work Step by Step
$12\frac{8}{15}$ + $18\frac{3}{5} + 14\frac{7}{10}$
Estimation:
$12\frac{8}{15}\approx 13$
$18\frac{3}{5} \approx 19$
$14\frac{7}{10} \approx 15$
Therefore
$12\frac{8}{15}$ + $18\frac{3}{5} + 14\frac{7}{10}$ $\approx$ 13 + 19 + 15 = 47
Exact Calculation:
$12\frac{8}{15}$ + $18\frac{3}{5} + 14\frac{7}{10}$
= $12\frac{8\times2}{15\times2}$ + $18\frac{3\times6}{5\times6}$ + $14\frac{7\times3}{10\times3}$
(30 is the least common denominator)
= $12\frac{16}{30}$ + $18\frac{18}{30}$ + $14\frac{21}{30}$
= $12$ +$18$ + $14$ + $\frac{16}{30}$ + $\frac{18}{30}$ + $\frac{21}{30}$
(Adding whole parts separately and fractional parts separately)
= $44$ + $\frac{16 + 18 + 21}{30}$
= $44$ + $\frac{55}{30}$
= $44$ + $\frac{30 + 25}{30}$
= $44$ + $\frac{30}{30} + \frac{25}{30} $
= 44 + 1 + $\frac{5}{6}$
= $45\frac{5}{6}$
The estimate was 47, so the exact answer of = $45\frac{5}{6}$
is reasonable.
