Please guess an idiom according to the characteristics of the formula. 0 + 0 = 11 × 1 = 11-1 = 2

Please guess an idiom according to the characteristics of the formula. 0 + 0 = 11 × 1 = 11-1 = 2

0 + 0 = 1 out of nothing
1 × 1 = 1 invariable
1-1 = 2