How do you know that the additive inverse of -20 is 20? Algebra Properties of Real Numbers Additive Inverses and Absolute Values 1 Answer seph Nov 22, 2014 A number N's additive inverse N' is a number that when added to N, will result to the additive identity, which is 0. 20 + N' = 0 => N' = -20 Answer link Related questions What are absolute values? What is the absolute value of -10 and 10? How do you evaluate |2-8|? How do you simplify -|-1|? What is the additive inverse property? What is the absolute value of -9? How do you simplify x = - abs6^2 - abs(-4 + 7) *7? How do you simplify abs( -11 +1)? How do you simplify abs6-abs(-3)? How do you simplify abs(1/5-1/3)? See all questions in Additive Inverses and Absolute Values Impact of this question 4523 views around the world You can reuse this answer Creative Commons License