Metamath Proof Explorer


Theorem 1pneg1e0

Description: 1 + -u 1 is 0. (Contributed by David A. Wheeler, 8-Dec-2018)

Ref Expression
Assertion 1pneg1e0 1 + -1 = 0

Proof

Step Hyp Ref Expression
1 ax-1cn 1
2 1 negidi 1 + -1 = 0