Metamath Proof Explorer
		
		
		
		Description:  Add two numerals M and N (with carry).  (Contributed by Mario
       Carneiro, 18-Feb-2014)  (Revised by AV, 6-Sep-2021)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | decma.a | ⊢ 𝐴  ∈  ℕ0 | 
					
						|  |  | decma.b | ⊢ 𝐵  ∈  ℕ0 | 
					
						|  |  | decma.c | ⊢ 𝐶  ∈  ℕ0 | 
					
						|  |  | decma.d | ⊢ 𝐷  ∈  ℕ0 | 
					
						|  |  | decma.m | ⊢ 𝑀  =  ; 𝐴 𝐵 | 
					
						|  |  | decma.n | ⊢ 𝑁  =  ; 𝐶 𝐷 | 
					
						|  |  | decaddc.e | ⊢ ( ( 𝐴  +  𝐶 )  +  1 )  =  𝐸 | 
					
						|  |  | decaddc2.t | ⊢ ( 𝐵  +  𝐷 )  =  ; 1 0 | 
				
					|  | Assertion | decaddc2 | ⊢  ( 𝑀  +  𝑁 )  =  ; 𝐸 0 | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | decma.a | ⊢ 𝐴  ∈  ℕ0 | 
						
							| 2 |  | decma.b | ⊢ 𝐵  ∈  ℕ0 | 
						
							| 3 |  | decma.c | ⊢ 𝐶  ∈  ℕ0 | 
						
							| 4 |  | decma.d | ⊢ 𝐷  ∈  ℕ0 | 
						
							| 5 |  | decma.m | ⊢ 𝑀  =  ; 𝐴 𝐵 | 
						
							| 6 |  | decma.n | ⊢ 𝑁  =  ; 𝐶 𝐷 | 
						
							| 7 |  | decaddc.e | ⊢ ( ( 𝐴  +  𝐶 )  +  1 )  =  𝐸 | 
						
							| 8 |  | decaddc2.t | ⊢ ( 𝐵  +  𝐷 )  =  ; 1 0 | 
						
							| 9 |  | 0nn0 | ⊢ 0  ∈  ℕ0 | 
						
							| 10 | 1 2 3 4 5 6 7 9 8 | decaddc | ⊢ ( 𝑀  +  𝑁 )  =  ; 𝐸 0 |