① 直接写出得数。(每题1分,共20分)
$12-6.8=$
$0.96÷0.3=$
$1.9+7.1=$
$4.8+0.2=$
$4.37+2.08=$
$15+27.4=$
$11-7.3=$
$168+279=$
$0.1×0.1=$
$75.3-18.4=$
$93.4-41.2=$
$98×0.02=$
$481+359=$
$509-326=$
$742+498=$
$101.6-23=$
$1.7+5.5=$
$37+46.6=$
$1.8×5=$
$2.6÷0.02=$

1.5.2
2.3.2
3.9
4.5
5.6.45
6.42.4
7.3.7
8.447
9.0.01
10.56.9
11.52.2
12.1.96
13.840
14.183
15.1240
16.78.6
17.7.2
18.83.6
19.9
20.130

② 计算。(每题3分,共18分)
$5.86×4+58.6×0.6$
$3.28÷0.4÷2.5$
$19999+1999+198+6$
$8.8÷[15.5-(1.7+2.8)]$
$15.43+5.9-3.43$
$0.23×7.6+7.6×0.77$

1.58.6
2.3.28
3.22202
4.0.8
5.17.9
6.7.6

③ 解方程。(每题4分,共12分)
$x-0.5x=20$
$0.85(x-6)=5.1$
$10-4x=8$

1.解:$x=40$
2.解:$x=12$
3.解:$x=0.5$