Metamath Proof Explorer
		
		
		
		Description:  Split a decimal number into two parts.  Base case: N = 0 .
       (Contributed by Mario Carneiro, 16-Jul-2015)  (Revised by AV, 8-Sep-2021)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypothesis | decsplit0.1 | ⊢ 𝐴  ∈  ℕ0 | 
				
					|  | Assertion | decsplit0b | ⊢  ( ( 𝐴  ·  ( ; 1 0 ↑ 0 ) )  +  𝐵 )  =  ( 𝐴  +  𝐵 ) | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | decsplit0.1 | ⊢ 𝐴  ∈  ℕ0 | 
						
							| 2 |  | 10nn0 | ⊢ ; 1 0  ∈  ℕ0 | 
						
							| 3 | 2 | numexp0 | ⊢ ( ; 1 0 ↑ 0 )  =  1 | 
						
							| 4 | 3 | oveq2i | ⊢ ( 𝐴  ·  ( ; 1 0 ↑ 0 ) )  =  ( 𝐴  ·  1 ) | 
						
							| 5 | 1 | nn0cni | ⊢ 𝐴  ∈  ℂ | 
						
							| 6 | 5 | mulridi | ⊢ ( 𝐴  ·  1 )  =  𝐴 | 
						
							| 7 | 4 6 | eqtri | ⊢ ( 𝐴  ·  ( ; 1 0 ↑ 0 ) )  =  𝐴 | 
						
							| 8 | 7 | oveq1i | ⊢ ( ( 𝐴  ·  ( ; 1 0 ↑ 0 ) )  +  𝐵 )  =  ( 𝐴  +  𝐵 ) |