Question 1203092
<pre>
1 0 0 0 

- 3 4 7
</pre>


{{{0-7}}}
positive whole number?
No.


{{{0-4}}}
positive whole number?
No.

{{{0-3}}}
positive whole number?
No.  


Look over on the left side, for the hundreds place.
10 hundred minus 3 hundred IS a whole number of hundreds.  But you need to borrow some of them before you can subtract within the TENS column.


First part of the borrowing is to start this way:

<pre>
0  10  0  0 

-  3  4  7
</pre>


and then
<pre>
0  9  10  0 

-  3  4  7
</pre>


and then still need to borrow for the ONES place:
<pre>
0  9  9  10 

-  3  4  7
</pre>
NOW the subtraction can be performed, column by column, from right to left.