How can you describe two numbers that add to zero?

I think it its 0 its called the additive identity because when you add it to a number, the result you get is the same number.

Step-by-step explanation:

For example, 5 + 0 = 5 Any two numbers whose sum is zero, such as 3 and -4, because 3 + (-3) = 0.

b

step-by-step explanation:

a difference is the result of subtraction. while each of these expressions has subtraction in it, a difference will be the result when subtraction is the last operation applied in the order of operations for the expression. this means subtraction must be outside of the parenthesis. only b has this.

1/800 is the right answer