1.把下面的小数化成分数，分数化成小数。（每题1★）
0.2=
0.3=
0.5=
0.6=
0.05=
0.13=
0.15=
0.25=
0.375=
0.045=
1.4=
3.25=
$\frac{27}{40}=$
$\frac{19}{4}=$
$\frac{7}{20}=$
$\frac{26}{5}=$
$\frac{9}{50}=$
$\frac{4}{25}=$
$\frac{13}{20}=$
$\frac{13}{5}=$

1. $0.2=\frac{1}{5}$
$0.3=\frac{3}{10}$
$0.5=\frac{1}{2}$
$0.6=\frac{3}{5}$
$0.05=\frac{1}{20}$
$0.13=\frac{13}{100}$
$0.15=\frac{3}{20}$
$0.25=\frac{1}{4}$
$0.375=\frac{3}{8}$
$0.045=\frac{9}{200}$
$1.4=\frac{7}{5}$
$3.25=3\frac{1}{4}$
$\frac{27}{40}=0.675$
$\frac{19}{4}=4.75$
$\frac{7}{20}=0.35$
$\frac{26}{5}=5.2$
$\frac{9}{50}=0.18$
$\frac{4}{25}=0.16$
$\frac{13}{20}=0.65$
$\frac{13}{5}=2.6$

2.计算下面各题,能简算的要简算。(每题3★)
$4×(2.5+1.25)$
$4.28×1.9+1.9×5.72$
$5.12÷(0.32×12.4÷6.2)$
$(7.8-5.8)×2.4+3.6$
$1.25×8.8×12.5$
$7.5×6.7+0.75×26+75×0.07$

2. $4×(2.5+1.25)=15$
$4.28×1.9+1.9×5.72=19$
$5.12÷(0.32×12.4÷6.2)=8$
$(7.8-5.8)×2.4+3.6=8.4$
$1.25×8.8×12.5=137.5$
$7.5×6.7+0.75×26+75×0.07=75$

3.解方程。（每题3★）
$1.9x + 5.1x = 14.7$
$9x - 4×6 = 4.8$
$7×(x - 2.5) = 25.2$

3. $x=2.1$ $x=3.2$ $x=6.1$