# How can we find  3 9/10 of 15/16? How could we check by estimating?

Apr 5, 2017

$= 3 \frac{21}{32}$

#### Explanation:

"Of" is the same as $\times$

$3 \frac{9}{10} \times \frac{15}{16}$

Change to an improper fraction.

$= \frac{39}{10} \times \frac{15}{16} \text{ } \leftarrow$ cancel where possible

$= \frac{39}{\cancel{10}} ^ 2 \times {\cancel{15}}^{3} / 16$

$= \frac{117}{32}$

$= 3 \frac{21}{32}$

If we estimate the answer we see that we are multiplying a number a little less than $4$ by a number just less than $1$.
We expect an answer a bit less than $4$.

$3 \frac{21}{32}$ is reasonable.