一、口算。
71 - 36 =
34 × 20 =
90 ÷ 18 =
1.7 × 5 =
0.5 + 0.35 =
1.92 - 0.09 =
225 ÷ 5 =
250 × 3 =
204 + 160 =
0.01 × 8 =
9.06 - 6.6 =
0.81 × 2 =
0.56 × 10 =
2400 ÷ 80 =
21.8 × 100 =
7.4 × 100 =
0.23 × 4 =
906 ÷ 6 =
2.461 × 10 =
170 × 50 =
0.26 × 1000 =
2.03 + 3.7 =
1.26 × 2 =
7.8 + 0.22 =
10 - 9.12 =
900 ÷ 45 =
1.2 × 20 =
420 ÷ 21 =
0.006 × 1000 =
0.05 × 11 =

1.35
2.680
3.5
4.8.5
5.0.85
6.1.83
7.45
8.750
9.364
10.0.08
11.2.46
12.1.62
13.5.6
14.30
15.2180
16.740
17.0.92
18.151
19.24.61
20.8500
21.260
22.5.73
23.2.52
24.8.02
25.0.88
26.20
27.24
28.20
29.6
30.0.55

二、在$□$里填合适的数。
$7.6×□=760$
$12.5×□=125$
$5.6×□=5600$
$0.32×□=32$
$1.23×□=123$
$3.57×□=3570$
$0.506×□=5.06$
$0.08×□=80$
$0.049×□=4.9$
$5.08×□=508$
$0.17×□=1700$
$0.26×□=26$
$2.04×□=204$
$0.0103×□=10.3$
$4.203×□=42030$

1.100
2.10
3.1000
4.100
5.100
6.1000
7.10
8.1000
9.100
10.100
11.10000
12.100
13.100
14.1000
15.10000