ADD: If both numbers are positive or negative then you have to add them if its a negative then your answer is a negative.6+1=7;-4+-1=-5
If one of the numbers are negative and the other one is positive then you will have to subtract.Then find the bigger number in the problem if its a negativie then your answer is a negative if your number is positive then your answer is a positive.-9+1=-8;4+-3=1
Sorry Don't Know What The Rules For Subtraction.But Hope This Helped You For Adding.
The mean is the average of the numbers. It is easy to calculate: add up all the numbers, then divide by how many numbers there are. In other words it is the sum divided by the count.