1. 直接写出得数。
2.55+1.6= 2.7−0.9= 3.6+1.4=
1.2+4.9= 12+0.12= 12.5×0.8=
5.4−0.26= 1.1×0.5= 1.6×0.8=
5.1−2.7= 9.8−2.3= 5.5+5.5=

2.55+1.6=4.15
2.7−0.9=1.8
3.6+1.4=5
1.2+4.9=6.1
12+0.12=12.12
12.5×0.8=10
5.4−0.26=5.14
1.1×0.5=0.55
1.6×0.8=1.28
5.1−2.7=2.4
9.8−2.3=7.5
5.5+5.5=11

2. 列竖式计算。
48.3+1.97= 5.48+2.19= 6.06−3.89=
40−3.29= 45×6.44= 5.63×0.94=

48.30
+ 1.97
-------
50.27
5.48
+ 2.19
-------
7.67
6.06
3.89
-------
2.17
40.00
3.29
-------
36.71
6.44
× 45
-------
3220
2576
-------
289.80
5.63
× 0.94
-------
2252
5067
-------
5.2922
（注：289.80可简化为289.8）

3. 计算下列各题，能简算的要简算。
62.2×4+17.8×4 8×(0.25+1.25)
2.55×7.1+2.45×7.1 18.4−5.6×1.5

62.2×4+17.8×4
=(62.2+17.8)×4
=80×4
=320
8×(0.25+1.25)
=8×0.25+8×1.25
=2+10
=12
2.55×7.1+2.45×7.1
=(2.55+2.45)×7.1
=5×7.1
=35.5
18.4−5.6×1.5
=18.4−8.4
=10