2 -
3
1
20 ×
5
4
2
2
9 +
5
8 ×
2
4
3 ÷
1
3
4
8 +
5
3
1 -
2
1
4 ÷
1
4
2 ÷
2
8 +
3
5
1 -
2
3
1
20 ×
5
4