1. 直接写出得数。
9.1+5.7= 9.8+3.2= 9.3-1.9= 3.6-1.6=
5.7+2.5= 3.9+2.2= 8.6-1.9= 7.7+1.2=
3.9+3.9= 5.8+1.9= 9.4-2.7= 8.2+1.6=
6.7+0.3= 8.5+2.5= 4.5-3.8= 5.3+4.5=
0.7+7.2= 3.2+5.4= 8.2-0.8= 2.6+5.6=

9.1 + 5.7 = 14.8 9.8 + 3.2 = 13 9.3 - 1.9 = 7.4 3.6 - 1.6 = 2
5.7 + 2.5 = 8.2 3.9 + 2.2 = 6.1 8.6 - 1.9 = 6.7 7.7 + 1.2 = 8.9
3.9 + 3.9 = 7.8 5.8 + 1.9 = 7.7 9.4 - 2.7 = 6.7 8.2 + 1.6 = 9.8
6.7 + 0.3 = 7 8.5 + 2.5 = 11 4.5 - 3.8 = 0.7 5.3 + 4.5 = 9.8
0.7 + 7.2 = 7.9 3.2 + 5.4 = 8.6 8.2 - 0.8 = 7.4 2.6 + 5.6 = 8.2

2. 脱式计算。
•6.8-4.9+1.2 •0.8-0.2+4.4 •16.1+2.2-9.7 •10.8+2.4-5.5

6.8 - 4.9 + A.2 0.8 - 0.2 + 4.4 16.1 + 2.2 - 9.7 10.8 + 2.4 - 5.5
= 1.9 + 1.2 = 0.6 + 4.4 = 18.3 - 9.7 = 13.2 - 5.5
= 3.1 = 5 = 8.6 = 7.7

3. 比一比。
4.69.1 15分米1.5米 54分米5.6米
8.90.8 1分米0.9米 2.7米26分米
2.98.2 3.2分米32厘米 7.4米71分米

4.6＜9.1 15分米 = 1.5米 54分米＜5.6米
8.9＞0.8 1分米＜0.9米 2.7米＞26分米
2.9＜8.2 3.2分米 = 32厘米 7.4米＞71分米

4. 算一算。