(a) I'd say sometimes true. 3 + -7= -4 , -5 + 3= -2 , 8+-5=3, 7+-7=0
(b) I'm not too sure about this one but I what i know is that if the positive number is higher than the negative number it will be a positive. If you are adding both a negative number and a positive number that is the same value it will be 0. And if you are adding a negative that is higher than the positive it will be a negative number.
