Metamath Proof Explorer


Theorem decsubi

Description: Difference between a numeral M and a nonnegative integer N (no underflow). (Contributed by AV, 22-Jul-2021) (Revised by AV, 6-Sep-2021)

Ref Expression
Hypotheses decaddi.1 A 0
decaddi.2 B 0
decaddi.3 N 0
decaddi.4 No typesetting found for |- M = ; A B with typecode |-
decaddci.5 A + 1 = D
decsubi.5 B N = C
Assertion decsubi Could not format assertion : No typesetting found for |- ( M - N ) = ; A C with typecode |-

Proof

Step Hyp Ref Expression
1 decaddi.1 A 0
2 decaddi.2 B 0
3 decaddi.3 N 0
4 decaddi.4 Could not format M = ; A B : No typesetting found for |- M = ; A B with typecode |-
5 decaddci.5 A + 1 = D
6 decsubi.5 B N = C
7 10nn0 10 0
8 7 1 nn0mulcli 10 A 0
9 8 nn0cni 10 A
10 2 nn0cni B
11 3 nn0cni N
12 9 10 11 addsubassi 10 A + B - N = 10 A + B - N
13 dfdec10 Could not format ; A B = ( ( ; 1 0 x. A ) + B ) : No typesetting found for |- ; A B = ( ( ; 1 0 x. A ) + B ) with typecode |-
14 4 13 eqtri M = 10 A + B
15 14 oveq1i M N = 10 A + B - N
16 dfdec10 Could not format ; A C = ( ( ; 1 0 x. A ) + C ) : No typesetting found for |- ; A C = ( ( ; 1 0 x. A ) + C ) with typecode |-
17 6 eqcomi C = B N
18 17 oveq2i 10 A + C = 10 A + B - N
19 16 18 eqtri Could not format ; A C = ( ( ; 1 0 x. A ) + ( B - N ) ) : No typesetting found for |- ; A C = ( ( ; 1 0 x. A ) + ( B - N ) ) with typecode |-
20 12 15 19 3eqtr4i Could not format ( M - N ) = ; A C : No typesetting found for |- ( M - N ) = ; A C with typecode |-