Is the sum of two rational numbers sometimes 0?

Answer 1

Yes. For example:

* 0 + 0 = 0

* 1/1 + (-1/1) = 0

* 1/2 + 1/3 is not equal to zero.

If the second rational number is the additive inverse of the first, then yes the sum of two rational numbers can be zero.

The additive inverse is that number when added to another number gives the result 0, and is denoted as the negative of the first number; the additive inverse of the number a is denoted by -(a) and is such that a + -(a) = 0.

eg the additive inverse of 1/2 is -(1/2) giving 1/2 + -(1/2) = 0.