Editing Subtraction (section)

===Nonvertical methods===
====Counting up====
Instead of finding the difference digit by digit, one can count up the numbers between the subtrahend and the minuend.<ref>[https://sites.google.com/a/oswego308.org/msimester/home/math/algorithms/subtraction The Many Ways of Arithmetic in UCSMP Everyday Mathematics] {{Webarchive|url=https://web.archive.org/web/20140225135251/https://sites.google.com/a/oswego308.org/msimester/home/math/algorithms/subtraction |date=2014-02-25 }} Subtraction: Counting Up</ref>

Example:
1234 − 567 = can be found by the following steps:
* {{nowrap|1=567 + '''3''' = 570}}
* {{nowrap|1=570 + '''30''' = 600}}
* {{nowrap|1=600 + '''400''' = 1000}}
* {{nowrap|1=1000 + '''234''' = 1234}}
Add up the value from each step to get the total difference: {{nowrap|1=3 + 30 + 400 + 234 = 667}}.

====Breaking up the subtraction====
Another method that is useful for [[Mental calculation|mental arithmetic]] is to split up the subtraction into small steps.<ref>[https://sites.google.com/a/oswego308.org/msimester/home/math/algorithms/subtraction The Many Ways of Arithmetic in UCSMP Everyday Mathematics] {{Webarchive|url=https://web.archive.org/web/20140225135251/https://sites.google.com/a/oswego308.org/msimester/home/math/algorithms/subtraction |date=2014-02-25 }} Subtraction: Left to Right Subtraction</ref>

Example:
1234 − 567 = can be solved in the following way:
* 1234 − '''500''' = 734
* 734 − '''60''' = 674
* 674 − '''7''' = 667

====Same change====
The same change method uses the fact that adding or subtracting the same number from the minuend and subtrahend does not change the answer. One simply adds the amount needed to get zeros in the subtrahend.<ref>[https://sites.google.com/a/oswego308.org/msimester/home/math/algorithms/subtraction The Many Ways of Arithmetic in UCSMP Everyday Mathematics] Subtraction: Same Change Rule</ref>

Example:

"1234 − 567 =" can be solved as follows:
* {{nowrap|1=1234 − 567 = 1237 − 570 =}} {{nowrap|1=1267 − 600 = 667}}