The sum of any number and its additive inverse gives the additive identity.
Additive Identity is a number that when added to any other number does not change it value. Eg. 2 + 0 = 2
Hence 0 is the additive identity for all numbers
Additive Inverse of 6 = (- 6)
Hence 6 + (- 6 )
= 6 - 6
= 0
The sum of 6 and its additive inverse is 0
