一、口算。
72÷0.36 =
11.9 - 9 =
42÷0.01 =
0.9×50 =
6.4÷0.32 =
1 + 3.89 =
3.6 + 5.4 =
35×0.01 =
9.6÷0.8 =
0.81×10 =
8.5 - 2.25 =
2.48 + 1.69 =
20.8÷4 =
1.5×7 =
2.8 - 1.45 =
10 - 0.08 =
0.35 + 0.5 =
0.125÷0.5 =
39÷130 =
1.78×100 =
4.8 + 5.2 =
12.1×0.3 =
1.32 - 1.2 =
5÷4 =
1.5 - 0.82 =
0.05×20 =
0.86 - 0.68 =
0.41 + 2.25 =
3.9÷0.39 =
3×0.2 =

200 2.9 4200
45 20 4.89
9 0.35 12
8.1 6.25 4.17
5.2 10.5 1.35
9.92 0.85 0.25
0.3 178 10
3.63 0.12 1.25
0.68 1 0.18
2.66 10 0.6

二、解方程。
1.2x + 17 = 41
48 - 5.1x = 7.2
10.5x + 6.5x = 51

$x = 20$ $x = 8$
$x = 3$