# How do you simplify 9.44\times 70.8?

Mar 23, 2017

$668.352$

#### Explanation:

$9.44 \times 70.8$

$\therefore = 9 \frac{44}{100} \times 70 \frac{8}{10}$

$\therefore = \frac{944}{100} \times \frac{708}{10}$

$\therefore = \frac{668352}{1000}$

$\therefore = 668.352$

Mar 24, 2017

$9.44 \times 70.8 = 668.352$

#### Explanation:

You can do long multiplication.

Ignore the decimal places for now:

$\textcolor{w h i t e}{\ldots \ldots \ldots . .} 944$
$\textcolor{w h i t e}{\ldots \ldots \ldots . .} \underline{\textcolor{b l u e}{7} 0 \textcolor{red}{8}}$
$\textcolor{w h i t e}{\ldots \ldots \ldots .} \textcolor{red}{7552} \text{ }$ multiply the top row by $\textcolor{red}{3}$
color(white)(.......)ul(color(blue)(660800)" " multiply the top row by $\textcolor{b l u e}{700}$
$\textcolor{w h i t e}{\ldots \ldots .} \underline{668352} \text{ }$add the two rows

(There was no point in multiplying by the middle number, 0)

Now count how many decimal places there were altogether in the original numbers. There were $3$ places.

$9 \textcolor{red}{.44} \times 70 \textcolor{red}{.8} = 668 \textcolor{red}{.352}$

There must be the same number of places in the final answer.

As a final check, do a quick estimate of the size of the answer.
$9 \times 70 = 630$

An answer of $668$ is in the right order of size.