Subtracting with Positive and Negative Integers
Subtraction is lame,
Keep the first number the same.
Avoid all the fuss,
Change minus to plus.
It will be fine,
After we change the next sign.
Finding Percent Change
Find the old and find the new,
Take the difference between the two.
Divide by the old amount you would have spent, Times by 100 to make a percent.