Use the algorithm method.
| | | | | | | 6 | 6 | 6 | 6 | 6 | 6 |
| × | | | | | | | 5 | 5 | 5 | 5 | 5 | 5 |
|
| | | | | | 3 | 3 | 3 | 3 | 3 | 3 | |
| | | | | | 3 | 3 | 3 | 3 | 3 | 3 | 0 |
| | | | | 3 | 3 | 3 | 3 | 3 | 3 | | |
| | | | | 3 | 3 | 3 | 3 | 3 | 3 | 0 | 0 |
| | | | 3 | 3 | 3 | 3 | 3 | 3 | | | |
| | | | 3 | 3 | 3 | 3 | 3 | 3 | 0 | 0 | 0 |
| | | 3 | 3 | 3 | 3 | 3 | 3 | | | | |
| | | 3 | 3 | 3 | 3 | 3 | 3 | 0 | 0 | 0 | 0 |
| | 3 | 3 | 3 | 3 | 3 | 3 | | | | | |
| | 3 | 3 | 3 | 3 | 3 | 3 | 0 | 0 | 0 | 0 | 0 |
| 3 | 3 | 3 | 3 | 3 | 3 | | | | | | |
| 3 | 3 | 3 | 3 | 3 | 3 | 0 | 0 | 0 | 0 | 0 | 0 |
|
| | 1 | 1 | 1 | 1 | 1 | 1 | | | | | |
| 3 | 7 | 0 | 3 | 6 | 9 | 6 | 2 | 9 | 6 | 3 | 0 |
Therefore, \(666666\times 555555=370369629630\).
\[370369629630\]
370369629630
