Description: Commute ones place in addition. (Contributed by Steven Nguyen, 29-Jan-2023)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | decaddcom.a | |- A e. NN0 |
|
| decaddcom.b | |- B e. NN0 |
||
| decaddcom.c | |- C e. NN0 |
||
| Assertion | decaddcom | |- ( ; A B + C ) = ( ; A C + B ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | decaddcom.a | |- A e. NN0 |
|
| 2 | decaddcom.b | |- B e. NN0 |
|
| 3 | decaddcom.c | |- C e. NN0 |
|
| 4 | eqid | |- ; A B = ; A B |
|
| 5 | eqid | |- ( B + C ) = ( B + C ) |
|
| 6 | 1 2 3 4 5 | decaddi | |- ( ; A B + C ) = ; A ( B + C ) |
| 7 | eqid | |- ; A C = ; A C |
|
| 8 | 3 | nn0cni | |- C e. CC |
| 9 | 2 | nn0cni | |- B e. CC |
| 10 | 8 9 | addcomi | |- ( C + B ) = ( B + C ) |
| 11 | 1 3 2 7 10 | decaddi | |- ( ; A C + B ) = ; A ( B + C ) |
| 12 | 6 11 | eqtr4i | |- ( ; A B + C ) = ( ; A C + B ) |