7 +
3
4
2 ×
1
2
8 +
5
20 ×
4
5
3 -
2
15 ×
1
3
2 ×
1
2
5
3
5 +
4
10 ×
2
2 -
3
12 ×
4
5
1
5
1
3
8 ×
4
2