① 直接写出得数。(每题1分,共20分)
$10-6.9-3.1=$
$3.4+3.9+2.6=$
$24-2.4-6.6=$
$6.3+2.7-5.8=$
$6.3+3.7-6.3=$
$5.8+6.3-3.4=$
$8-5.3+2.8=$
$8.5+4.3-1.7=$
$9.2-7.5+5.8=$
$5-2.5-1.4=$
$1.6+3.4-2.4=$
$3.6+2.7+6.4=$
$1.3+6.7+4.3=$
$3.6+7.5-2.6=$
$6.4-2.7+1.8=$
$3.5+4.2+2.5=$
$5.8+0.3-2.7=$
$4.7+3.6-2.1=$
$7.9-4.3+2.7=$
$11-3.4+7.7=$

1.0
9.9
15
3.2
3.7
8.7
5.5
11.1
7.5
1.1
2.6
12.7
12.3
8.5
5.5
10.2
3.4
6.2
6.3
15.3

② 列竖式计算。(每题3分,共12分)
200 - 98.74 =
78.7 - 38.37 =
3.61 + 8.2 =
40.75 + 3.47 =

竖式略
101.26
40.33
11.81
44.22

③ 计算下面各题,能简算的要简算。(每题3分,共18分)
$3.69+9.85+6.31$
$60.7-(10.65-2.72)$
$8-3.27+2.27$
$13.7-(3.7-0.38)$
$12.57-7.49-2.51$
$3.75+2.43+1.25+0.57$

19.85
52.77
7
10.38
2.57
8