Question

# Having difficulties with signed numbers when it comes to multiplication, division, addition and subtraction. Is there a simpler way to remember how to use the signs in math problems?

Negative numbers and coordinate plane
Having difficulties with signed numbers when it comes to multiplication, division, addition and subtraction. Is there a simpler way to remember how to use the signs in math problems?

2021-03-08
Let two negative numbers be -a and -b. For example : -2 and -5.
Let us consider the rules for individual arithmatic operations:
-a+(-b): negative
e.g, -2+(-5)=-7
Substraction of 2 negative numbers:
(-a)-(-b) is negtive if |a|>|b| and positive therwise.
e.g, (-2)-(-5)=-2+5=3 (positive) as |-2|
Multiplication of 2 negative numbers:
(-a)*(-b)=ab: positive
e.g., (-2)*(-5)=10
Division of 2 negative numbers:
$$\displaystyle-\frac{{a}}{{-{{b}}}}$$: positive
e.g, $$\displaystyle-\frac{{2}}{{-{{5}}}}={0.40}$$