Math rules.

addition rules

A + sign means you add!

1. 2 positive integers equals a positive answer.
2. 2 negative integers equals a negative answer
3. if the signs are different subtract and see which original number was the largest then that is weather it is positive or negative.

subtraction rules

I can explain this only through an example.

+5 - (+2)

keep-it change-it change-it

+5 + (-2)

Then go to addition rules.

Multiplication rules

1. If the signs are different then it is a negative
2. If the signs are the same then it is a positive

Dividing rules.

The same as multiplication.