# What is the difference of 9.4-7.9?

Jul 10, 2016

1.5

#### Explanation:

$9.4 - 7.9$ = 1.5

You can check this answer by adding 7.9 to 1.5 and you will end up with 9.4.

Jul 12, 2016

Solution method taken one step at a time with a lot of detail

$1.5$

#### Explanation:

$\textcolor{b l u e}{\text{This is how the process should look and it is very quick:}}$

$\textcolor{w h i t e}{. .} {\cancel{9}}^{8} . {\cancel{4}}^{14}$
$\textcolor{w h i t e}{. .} \underline{7 \textcolor{w h i t e}{. .} .9}$
$\textcolor{w h i t e}{. .} 1 \textcolor{w h i t e}{. .} .5$

$\textcolor{w h i t e}{. .}$
$\textcolor{w h i t e}{. .}$

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$\textcolor{b l u e}{\text{This is the very detailed explanation}}$

Write as:
$\text{ } 9.4$
$\text{ "ul(7.9) larr" Subtract}$

Work from right to left
'~~~~~~~~~~~~~~~~~~~~~~~~~~~
$\textcolor{g r e e n}{\text{Subtracting the right column}}$

Notice that the right hand column the 4 is less than the 9.

For subtracting this part we have $\textcolor{red}{9 + \frac{4}{10}} \textcolor{b l u e}{- \frac{9}{10}}$

This is the same as $\textcolor{red}{8 + \frac{14}{10}} \textcolor{b l u e}{- \frac{9}{10}}$

So in our subtraction of the right column, instead of having:

$\textcolor{w h i t e}{.} 9 \textcolor{m a \ge n t a}{.4}$
$\underline{\textcolor{w h i t e}{. .} \textcolor{m a \ge n t a}{.9}} \leftarrow \text{ Subtract}$

We have:
$\textcolor{w h i t e}{.} 8 \textcolor{m a \ge n t a}{. {\cancel{4}}^{14}}$
$\underline{\textcolor{w h i t e}{\ldots .} \textcolor{m a \ge n t a}{.9}} \leftarrow \text{ Subtract}$
$\textcolor{w h i t e}{\ldots .} \textcolor{m a \ge n t a}{.5}$
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$\textcolor{g r e e n}{\text{Subtracting the left column}}$

$\textcolor{w h i t e}{. .} \textcolor{m a \ge n t a}{8} . {\cancel{4}}^{14}$
$\underline{\textcolor{w h i t e}{. .} \textcolor{m a \ge n t a}{7} .9} \leftarrow \text{ Subtract}$
$\textcolor{w h i t e}{\ldots} \textcolor{m a \ge n t a}{1} .5$

$\textcolor{w h i t e}{. .}$