Description: 5 times 4 equals 20. (Contributed by Mario Carneiro, 19-Apr-2015) (Revised by AV, 6-Sep-2021)
Ref | Expression | ||
---|---|---|---|
Assertion | 5t4e20 | |- ( 5 x. 4 ) = ; 2 0 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 5nn0 | |- 5 e. NN0 |
|
2 | 3nn0 | |- 3 e. NN0 |
|
3 | df-4 | |- 4 = ( 3 + 1 ) |
|
4 | 5t3e15 | |- ( 5 x. 3 ) = ; 1 5 |
|
5 | 1nn0 | |- 1 e. NN0 |
|
6 | eqid | |- ; 1 5 = ; 1 5 |
|
7 | 1p1e2 | |- ( 1 + 1 ) = 2 |
|
8 | 5p5e10 | |- ( 5 + 5 ) = ; 1 0 |
|
9 | 5 1 1 6 7 8 | decaddci2 | |- ( ; 1 5 + 5 ) = ; 2 0 |
10 | 1 2 3 4 9 | 4t3lem | |- ( 5 x. 4 ) = ; 2 0 |