Metamath Proof Explorer


Theorem 8t5e40

Description: 8 times 5 equals 40. (Contributed by Mario Carneiro, 19-Apr-2015) (Revised by AV, 6-Sep-2021)

Ref Expression
Assertion 8t5e40 85=40

Proof

Step Hyp Ref Expression
1 8nn0 80
2 4nn0 40
3 df-5 5=4+1
4 8t4e32 84=32
5 3nn0 30
6 2nn0 20
7 eqid 32=32
8 3p1e4 3+1=4
9 8cn 8
10 2cn 2
11 8p2e10 8+2=10
12 9 10 11 addcomli 2+8=10
13 5 6 1 7 8 12 decaddci2 32+8=40
14 1 2 3 4 13 4t3lem 85=40