15×68=1020;
1 5
×
6 8
1 2 0
9 0 1 0 2 0
验算:
6 8
15
1 0 2 0
9 0 1 2 0
1 2 0 0
522÷4=130…2;
1 3 0
4
5 2 2
5 2 0 2
1 3 0
×
4
5 2 0
+ 2 5 2 2
32×26=832;
3 2
×
2 6
1 9 2
6 4 8 3 2
927÷3=309.
3 0 9
3
9 2 7