一、口算。
3.5 - 0.2 =
3.1 + 4.6 =
5.8 - 2.7 =
5.2 + 6.6 =
4.3 - 2.1 =
7.2 + 1.5 =
9.9 - 8.6 =
3.3 + 3.3 =
8.7 - 3.4 =
4.2 + 6.5 =
7.7 - 2.5 =
1.5 + 6.4 =
8.2 - 5.2 =
6.7 + 4.1 =
9.4 - 8.2 =
2.8 + 0.1 =
8.9 - 7.8 =
6.2 + 0.7 =
5.8 - 3.4 =
1.1 + 5.7 =
8.9 - 5.5 =
1.1 + 7.2 =
9.2 - 0.1 =
8.6 + 4.2 =
5.7 - 1.4 =
4.1 + 5.3 =
3.9 - 1.2 =
2.3 + 3.6 =
7.5 - 7.4 =
5.4 + 3.5 =

3.3 7.7 3.1
11.8 2.2 8.7
1.3 6.6 5.3
10.7 5.2 7.9
3 10.8 1.2
2.9 1.1 6.9
2.4 6.8 3.4
8.3 9.1 12.8
4.3 9.4 2.7
5.9 0.1 8.9

二、用竖式计算。
51.2 - 46.8
7.9 + 24.7
21.3 - 4.6

4.4 32.6 16.7