| Step | Hyp | Ref | Expression | 
						
							| 1 |  | nnz |  |-  ( M e. NN -> M e. ZZ ) | 
						
							| 2 |  | nnne0 |  |-  ( M e. NN -> M =/= 0 ) | 
						
							| 3 | 1 2 | jca |  |-  ( M e. NN -> ( M e. ZZ /\ M =/= 0 ) ) | 
						
							| 4 |  | dvdsval2 |  |-  ( ( M e. ZZ /\ M =/= 0 /\ N e. ZZ ) -> ( M || N <-> ( N / M ) e. ZZ ) ) | 
						
							| 5 | 4 | 3expa |  |-  ( ( ( M e. ZZ /\ M =/= 0 ) /\ N e. ZZ ) -> ( M || N <-> ( N / M ) e. ZZ ) ) | 
						
							| 6 | 3 5 | sylan |  |-  ( ( M e. NN /\ N e. ZZ ) -> ( M || N <-> ( N / M ) e. ZZ ) ) | 
						
							| 7 |  | zre |  |-  ( N e. ZZ -> N e. RR ) | 
						
							| 8 |  | nnrp |  |-  ( M e. NN -> M e. RR+ ) | 
						
							| 9 |  | mod0 |  |-  ( ( N e. RR /\ M e. RR+ ) -> ( ( N mod M ) = 0 <-> ( N / M ) e. ZZ ) ) | 
						
							| 10 | 7 8 9 | syl2anr |  |-  ( ( M e. NN /\ N e. ZZ ) -> ( ( N mod M ) = 0 <-> ( N / M ) e. ZZ ) ) | 
						
							| 11 | 6 10 | bitr4d |  |-  ( ( M e. NN /\ N e. ZZ ) -> ( M || N <-> ( N mod M ) = 0 ) ) |