一、口算。
0.7 + 3.1 = 1.3 + 3.4 = 2.8 + 1.1 =
3.4 - 1.2 = 9.4 - 2.3 = 0.9 - 0.3 =
2.3 + 1.5 = 1.4 + 1.5 = 2.2 + 0.7 =
1.8 - 0.7 = 2.2 + 3.1 = 4.6 - 2.5 =
0.8 + 2.1 = 6.3 - 1.4 = 7.3 - 5.2 =
2.4 + 0.3 = 1.2 + 4.2 = 5.7 - 1.9 =
3.7 - 3.5 = 2.9 - 0.5 = 1.4 + 4.1 =
4.3 - 2.6 = 1.2 + 5.4 = 2.6 + 4.3 =
1.4 + 0.5 = 1.7 - 1.6 = 3.7 + 1.5 =
0.9 - 0.6 = 3.3 - 1.1 = 5.8 + 2.1 =
4.3 + 0.3 = 4.3 + 2.9 = 3.6 - 2.3 =
4.8 - 0.7 = 1.2 + 3.7 = 7.5 - 2.8 =
7.4 - 3.2 = 6.2 + 1.4 = 0.5 + 3.4 =
6.2 - 5.4 = 1.1 + 2.2 = 3.3 + 1.5 =
2.9 - 2.9 = 3.1 + 2.5 = 8.1 - 5.6 =
4.4 + 0.5 = 4.9 - 4.1 = 3.6 + 5.3 =
2.1 + 0.7 = 5.4 - 4.5 = 5.7 - 3.4 =
1.5 - 1.2 = 2.2 + 3.3 = 4.8 - 2.6 =
5.7 - 1.8 = 9.2 - 5.1 = 1.5 + 2.4 =
0.3 + 2.5 = 1.1 + 4.5 = 2.4 - 0.3 =

一、3.8 4.7 3.9
2.2 7.1 0.6
3.8 2.9 2.9
1.1 5.3 2.1
2.9 4.9 2.1
2.7 5.4 3.8
0.2 2.4 5.5
1.7 6.6 6.9
1.9 0.1 5.2
0.3 2.2 7.9
4.6 7.2 1.3
4.1 4.9 4.7
4.2 7.6 3.9
0.8 3.3 4.8
0 5.6 2.5
4.9 0.8 8.9
2.8 0.9 2.3
0.3 5.5 2.2
3.9 4.1 3.9
2.8 5.6 2.1