Answer
Estimated answer = 22
Exact answer = $22\frac{7}{30}$
Work Step by Step
$28\frac{3}{10}$ - $6\frac{1}{15}$
Estimation:
$28\frac{3}{10} \approx 28$
$6\frac{1}{15} \approx 6$
Therefore
$28\frac{3}{10}$ - $6\frac{1}{15}$ $\approx$ 28 - 6 = 22
Exact Calculation:
$28\frac{3}{10}$ - $6\frac{1}{15}$
= $28\frac{3\times3}{10\times3}$ - $6\frac{1\times2}{15\times2}$
(30 is the least common denominator)
= $28\frac{9}{30}$ - $6\frac{2}{30}$
= $28$ + $\frac{9}{30}$ - ($6$ + $\frac{2}{30})$
= $28$ + $\frac{9}{30}$ - $6$ - $\frac{2}{30}$
= ($28$ - $6$) + ($\frac{9}{30}$ - $\frac{2}{30}$)
(Solving whole parts separately and fractional parts separately)
= $22$ + $\frac{9 - 2}{30}$
= $22$ + $\frac{7}{30}$
= $22\frac{7}{30}$
The estimate was 22, so the exact answer of $22\frac{7}{30}$
is reasonable.
