Description: Associative law for addition. (Contributed by Mario Carneiro, 27-May-2016)
Ref | Expression | ||
---|---|---|---|
Hypotheses | addcld.1 | |
|
addcld.2 | |
||
addassd.3 | |
||
Assertion | addassd | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | addcld.1 | |
|
2 | addcld.2 | |
|
3 | addassd.3 | |
|
4 | addass | |
|
5 | 1 2 3 4 | syl3anc | |