Arithmetic With Negative Numbers
A minus number minus another number puts you 'deeper in debt'.
Example: -4 x -5 =20 but -5-4=-9.
-10/-2=5 and -10-2=-12
One reason people might get confused is because when they work out -(-5) the answer is 5, so the rule makes sense here, but we can write -(-5) as -1 x -5.
The best way to be sure is to rephrase the rule as 'minus times or divide minus equal plus', and remember these examples.
When adding or taking away negative numbers, be methodical.
Example: -4 -(-7)=-4+7=7-5=3.
These examples illustrate that the order in which you add or take away numbers does not matter, but you must be careful to make sure that the sign of each number does not change if you change the order of the number.