一、口算。（每题1分，共24分）
$2×50.5=$ $33×0.5=$ $3.9×5=$ $11.5×0.8=$
$0.2×3.5=$ $96×0.25=$ $20.3×0.7=$ $1.6×0.9=$
$3.6×0.5=$ $7.7×0.7=$ $0.4×1.6=$ $9.3×0.3=$
$0.7×5.1=$ $5.5×0.6=$ $0.2×25.4=$ $400×1.5=$
$3.2×0.4=$ $6.7×0.4=$ $2.7×0.3=$ $1.8×200=$
$2.5×6.4=$ $1.2×8=$ $100×19.9=$ $0.5×6.8=$

2×50.5=101
33×0.5=16.5
3.9×5=19.5
11.5×0.8=9.2
0.2×3.5=0.7
96×0.25=24
20.3×0.7=14.21
1.6×0.9=1.44
3.6×0.5=1.8
7.7×0.7=5.39
0.4×1.6=0.64
9.3×0.3=2.79
0.7×5.1=3.57
5.5×0.6=3.3
0.2×25.4=5.08
400×1.5=600
3.2×0.4=1.28
6.7×0.4=2.68
2.7×0.3=0.81
1.8×200=360
2.5×6.4=16
1.2×8=9.6
100×19.9=1990
0.5×6.8=3.4

二、在○里填上“＞”“＜”或“=”。（每空1.5分，共9分）
1. $1.15×0.98$○$1.15$
$0.36×28.2$○$3.6×2.82$
$0.88$○$0.88×0.88$
$2.31×0.79$○$0.97×2.31$
$45.6×1.03$○$45.6$
$4.28×0.99$○$0.9×4.25$

1. $1.15×0.98$＜$1.15$
$0.36×28.2$=$3.6×2.82$
$0.88$＞$0.88×0.88$
$2.31×0.79$＜$0.97×2.31$
$45.6×1.03$＞$45.6$
$4.28×0.99$＞$0.9×4.25$

三、根据已知的算式填一填。（每空1分，共8分）
104×5=520
25×32=800
10.4×5=()
2.5×3.2=()
104×0.05=()
0.25×3.2=()
1.04×0.5=()
0.25×0.32=()
0.104×0.5=()
25×0.032=()

10.4×5=52
2.5×3.2=8
104×0.05=5.2
0.25×3.2=0.8
1.04×0.5=0.52
0.25×0.32=0.08
0.104×0.5=0.052
25×0.032=0.8

四、用竖式计算。（每题3分，共18分）
3.7×15.8=
21.2×1.7=
40.1×2.8≈
（得数保留一位小数）
1.75×5.2=
22.3×5.1=
0.24×6.7≈
（得数保留两位小数）

3.7×15.8=58.46
21.2×1.7=36.04
40.1×2.8≈112.3
1.75×5.2=9.1
22.3×5.1=113.73
0.24×6.7≈1.61