Depends how you mean "add".
If you mean something like -7 + 4, then look at which number is larger. The larger number subtracted by the smaller number gives you the resulting value, and if the larger number is the negative one, then the resulting value is negative. so -7 + 4 = - (7 -4) = - (3) = -3
Consider positives as "removing" negative values, and negatives "removing" positive values. It's easier to work this way as long as you identify which value is bigger.
If you mean adding a negative number as though it was a positive number, this is represented as "|x|" meaning you get the value of x in it's positive form (So if x = -8 then |x| = 8, and if x = 4 then |x| = 4).
Depends how you mean "add".
If you mean something like -7 + 4, then look at which number is larger. The larger number subtracted by the smaller number gives you the resulting value, and if the larger number is the negative one, then the resulting value is negative. so -7 + 4 = - (7 -4) = - (3) = -3
Consider positives as "removing" negative values, and negatives "removing" positive values. It's easier to work this way as long as you identify which value is bigger.
If you mean adding a negative number as though it was a positive number, this is represented as "|x|" meaning you get the value of x in it's positive form (So if x = -8 then |x| = 8, and if x = 4 then |x| = 4).