Here are some rule : I will take 9 as first number and 4 as second number in the example

If both the number have negative sign (-) then you will add both the number and put "-" sign with the end result e.g -9-4= - 13

If one number has negative sign "-" and other has positive "+" sign then you will subtract the number and put the sign of the biggest number with the end result. E.g

As in question

First number is - 9

Second number is +4

You will subtract 9 from 4 and put the sign of bigger number with the end result. So the answer is

-9 + 4 =

If both the number have negative sign (-) then you will add both the number and put "-" sign with the end result e.g -9-4= - 13

If one number has negative sign "-" and other has positive "+" sign then you will subtract the number and put the sign of the biggest number with the end result. E.g

As in question

First number is - 9

Second number is +4

You will subtract 9 from 4 and put the sign of bigger number with the end result. So the answer is

-9 + 4 =

**- 5 >>> answer**