Description: Adding two times 1 to a number. (Contributed by AV, 22-Sep-2018)
Ref | Expression | ||
---|---|---|---|
Assertion | add1p1 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | id | |
|
2 | 1cnd | |
|
3 | 1 2 2 | addassd | |
4 | 1p1e2 | |
|
5 | 4 | a1i | |
6 | 5 | oveq2d | |
7 | 3 6 | eqtrd | |