一、口算。
3÷0.5 =
9.4×0.2 =
1.8÷0.9×0.5 =
20×0.02 =
7.4 - 0.56 =
67.2×99 + 67.2 =
6.4÷2 =
10×2.5 =
0.2×(0.4÷0.02) =
6 - 2.2 =
0.15 + 0.46 =
25×4÷0.25×4 =
0.12×5 =
7.2÷0.9 =
9÷5 - 1.9÷5 =
0.37 + 0.73 =
3.5×0.8 =
37.2×95 + 37.2×5 =
0.64×5 =
7.8 + 0.22 =
2 - 0.64 - 0.36 =
3.6 - 2.45 =
9.6÷0.12 =
0.8×(0.5÷0.2) =
4.3 + 5.07 =
9.58 - 4.5 =
0.3÷0.15×0.09 =
4÷0.4 =
1.5×0.6 =
0.56 + 0.6×0.8 =

6 1.88 1
0.4 6.84 6720
3.2 25 4
3.8 0.61 1600
0.6 8 1.42
1.1 2.8 3720
3.2 8.02 1
1.15 80 2
9.37 5.08 0.18
10 0.9 1.04

二、解方程。
x - 0.05x = 5.7
5x + 12.5 = 32.3
6x - 12.8×3 = 0.06

$x = 6$ $x = 3.96$
$x = 6.41$