一、口算。
$900÷ 45=$
$72÷ 12=$
$360÷ 40=$
$24× 20=$
$120÷ 40=$
$71+29=$
$150÷ 75=$
$32× 3=$
$140× 6=$
$100-25=$
$38÷ 19=$
$56÷ 28=$
$309÷ 3=$
$480÷ 48=$
$820÷ 41=$
$600÷ 15=$
$120-40=$
$80× 40=$
$180× 5=$
$520÷ 40=$
$560÷ 8=$
$360÷ 18=$
$960÷ 60=$
$240÷ 12=$

1.20
2.6
3.9
4.480
5.3
6.100
7.2
8.96
9.840
10.75
11.2
12.2
13.103
14.10
15.20
16.40
17.80
18.3200
19.900
20.13
21.70
22.20
23.16
24.20

二、用竖式计算，并验算。
$480÷50=$ $130÷20=$ $620÷30=$
$650÷80=$ $720÷70=$ $770÷60=$

1.$9······30$
2.$6······10$
3.$20······20$
4.$8······10$
5.$10······20$
6.$12······50$