7.2 Whole numbers: subtraction

$8-5=3$ since $3+5=8$ .

$9-3=6$ since $6+3=9$ .

The process of subtracting whole numbers

To subtract two whole numbers,

The process

1. Write the numbers vertically, placing corresponding positions in the same column.
   

   $\begin{array}{c}\hfill 48\\ \hfill \underline{-35}\end{array}$

2. Subtract the digits in each column. Start at the right, in the ones position, and move to the left, placing the difference at the bottom.
   

   $\begin{array}{c}\hfill 48\\ \hfill \underline{-35}\\ \hfill 13\end{array}$

$\begin{array}{c}\hfill 275\\ \hfill \underline{-142}\\ \hfill 133\end{array}$

$\begin{array}{}5-2=3\text{.}\\ 7-4=3\text{.}\\ 2-1=1\text{.}\end{array}$

$\begin{array}{c}\hfill \mathrm{46,042}\\ \hfill \underline{-\mathrm{ 1,031}}\\ \hfill \mathrm{45,011}\end{array}$

$\begin{array}{}2-1=1\text{.}\\ 4-3=1\text{.}\\ 0-0=0\text{.}\\ 6-1=5\text{.}\\ 4-0=4\text{.}\end{array}$

Find the difference between 977 and 235.

Write the numbers vertically, placing the larger number on top. Line up the columns properly.

$\begin{array}{c}\hfill 977\\ \hfill \underline{-235}\\ \hfill 742\end{array}$

The difference between 977 and 235 is 742.

In Keys County in 1987, there were 809 cable television installations. In Flags County in 1987, there were 1,159 cable television installations. How many more cable television installations were there in Flags County than in Keys County in 1987?

We need to determine the difference between 1,159 and 809.

There were 350 more cable television installations in Flags County than in Keys County in 1987.