2 0 9
乘 4 6
---------------
1 2 5 4
8 3 6
---------------
9 6 1 4
3 7 2
乘 3 8
-------------------
2 9 7 6
1 1 1 6
--------------------
1 4 1 3 6
315
乘 41
----------------
315
1260
----------------
12915
305
乘 41
----------------
305
1220
----------------
12505