一、口算。
0.125×2 =
1.8 - 0.82 =
4×1.25×0.25 =
0.12 + 0.08 =
0.8×1.5 =
0.2×16 - 0.2 =
680÷68 =
2.01 + 1.99 =
16 - (5.5 - 4.5) =
4.2×3 =
3.72÷4 =
2.5 - 3.6÷1.8 =
12.4 - 1.4 =
0.68 + 0.4 =
(0.8 - 0.18)÷2 =
300×0.7 =
0.81÷0.9 =
7.2 - 1.2 + 6.6 =
0.85 + 0.35 =
1.26 - 0.25 =
5×(0.01÷0.1) =
1.25÷0.5 =
3.2×0.6 =
(0.15 - 0.03)÷0.03 =
3.2 - 1.02 =
13.6 + 2.45 =
0.17 + 0.33 + 1.2 =
6.3÷0.021 =
8.8÷40 =
0.81÷0.9 - 0.15 =

0.25 0.98 1.25
0.2 1.2 3
10 4 15
12.6 0.93 0.5
11 1.08 0.31
210 0.9 12.6
1.2 1.01 0.5
2.5 1.92 4
2.18 16.05 1.7
300 0.22 0.75

二、解方程。
4.2x - 0.8 = 7.6
0.2x + 3.2×0.6 = 4.5
8(x - 7.4) = 22.4

$x = 2$ $x = 12.9$
$x = 10.2$