| Step | Hyp | Ref | Expression | 
						
							| 1 |  | decma.a |  |-  A e. NN0 | 
						
							| 2 |  | decma.b |  |-  B e. NN0 | 
						
							| 3 |  | decma.c |  |-  C e. NN0 | 
						
							| 4 |  | decma.d |  |-  D e. NN0 | 
						
							| 5 |  | decma.m |  |-  M = ; A B | 
						
							| 6 |  | decma.n |  |-  N = ; C D | 
						
							| 7 |  | decma2c.p |  |-  P e. NN0 | 
						
							| 8 |  | decma2c.f |  |-  F e. NN0 | 
						
							| 9 |  | decma2c.g |  |-  G e. NN0 | 
						
							| 10 |  | decma2c.e |  |-  ( ( P x. A ) + ( C + G ) ) = E | 
						
							| 11 |  | decma2c.2 |  |-  ( ( P x. B ) + D ) = ; G F | 
						
							| 12 |  | 10nn0 |  |-  ; 1 0 e. NN0 | 
						
							| 13 |  | dfdec10 |  |-  ; A B = ( ( ; 1 0 x. A ) + B ) | 
						
							| 14 | 5 13 | eqtri |  |-  M = ( ( ; 1 0 x. A ) + B ) | 
						
							| 15 |  | dfdec10 |  |-  ; C D = ( ( ; 1 0 x. C ) + D ) | 
						
							| 16 | 6 15 | eqtri |  |-  N = ( ( ; 1 0 x. C ) + D ) | 
						
							| 17 |  | dfdec10 |  |-  ; G F = ( ( ; 1 0 x. G ) + F ) | 
						
							| 18 | 11 17 | eqtri |  |-  ( ( P x. B ) + D ) = ( ( ; 1 0 x. G ) + F ) | 
						
							| 19 | 12 1 2 3 4 14 16 7 8 9 10 18 | numma2c |  |-  ( ( P x. M ) + N ) = ( ( ; 1 0 x. E ) + F ) | 
						
							| 20 |  | dfdec10 |  |-  ; E F = ( ( ; 1 0 x. E ) + F ) | 
						
							| 21 | 19 20 | eqtr4i |  |-  ( ( P x. M ) + N ) = ; E F |