一、口算。
$6×41=$
$600×7=$
$272+226=$
$200-88=$
$51×5=$
$230-50=$
$4×28=$
$612-0=$
$0×710=$
$82-63=$
$180×5=$
$636+130=$
$92×6=$
$80+132=$
$800-80=$
$3×501=$
$68-39=$
$146+214=$
$21×3=$
$2×320=$
$123×4=$
$89×6≈$
$303×3≈$
$697×4≈$

1.246
2.4200
3.498
4.112
5.255
6.180
7.112
8.612
9.0
10.19
11.900
12.766
13.552
14.212
15.720
16.1503
17.29
18.360
19.63
20.640
21.492
22.540
23.900
24.2800

二、用竖式计算。
$99×8=$
$6×365=$
$9×408=$
$387×4=$
$246×5=$
$410×8=$

1.792
2.2190
3.3672
4.1548
5.1230
6.3280