| Step | Hyp | Ref | Expression | 
						
							| 1 |  | decaddcom.a |  | 
						
							| 2 |  | decaddcom.b |  | 
						
							| 3 |  | decaddcom.c |  | 
						
							| 4 |  | eqid | Could not format  ; A B = ; A B : No typesetting found for |- ; A B = ; A B with typecode |- | 
						
							| 5 |  | eqid |  | 
						
							| 6 | 1 2 3 4 5 | decaddi | Could not format  ( ; A B + C ) = ; A ( B + C ) : No typesetting found for |- ( ; A B + C ) = ; A ( B + C ) with typecode |- | 
						
							| 7 |  | eqid | Could not format  ; A C = ; A C : No typesetting found for |- ; A C = ; A C with typecode |- | 
						
							| 8 | 3 | nn0cni |  | 
						
							| 9 | 2 | nn0cni |  | 
						
							| 10 | 8 9 | addcomi |  | 
						
							| 11 | 1 3 2 7 10 | decaddi | Could not format  ( ; A C + B ) = ; A ( B + C ) : No typesetting found for |- ( ; A C + B ) = ; A ( B + C ) with typecode |- | 
						
							| 12 | 6 11 | eqtr4i | Could not format  ( ; A B + C ) = ( ; A C + B ) : No typesetting found for |- ( ; A B + C ) = ( ; A C + B ) with typecode |- |