1. 直接写出得数。
$0.15 + 0.05 =$ $0.2 - 0.03 =$ $8.7 + 0.5 =$
$1.3 - 0.8 =$ $4.21 + 0.59 =$ $7.85 - 0.7 =$
$4.38 + 4.5 =$ $9.04 - 8.01 =$ $4.8×0.2 =$
$0.19×3 =$ $3.3×4 =$ $10.1×3 =$
$0.568×10 =$ $1.4×6 =$ $18×0.01 =$
$8.8×2 =$ $2.99 + 8 =$ $1.21×3 =$
$5.3 - 3.7 =$ $2.5×4 =$ $1.8×5 =$

0.15 + 0.05 = 0.2
0.2 - 0.03 = 0.17
8.7 + 0.5 = 9.2
1.3 - 0.8 = 0.5
4.21 + 0.59 = 4.8
7.85 - 0.7 = 7.15
4.38 + 4.5 = 8.88
9.04 - 8.01 = 1.03
4.8×0.2 = 0.96
0.19×3 = 0.57
3.3×4 = 13.2
10.1×3 = 30.3
0.568×10 = 5.68
1.4×6 = 8.4
18×0.01 = 0.18
8.8×2 = 17.6
2.99 + 8 = 10.99
1.21×3 = 3.63
5.3 - 3.7 = 1.6
2.5×4 = 10
1.8×5 = 9

2. 列竖式计算。
$45 - 3.92 =$ $4.85×6.2 =$
$0.47×2.18 =$ $55.18 + 54.828 =$

45.00
3.92
--------
41.08
$45 - 3.92 = 41.08$
4.85
× 6.2
--------
970
2910
--------
30.070
$4.85×6.2 = 30.07$
0.47
×2.18
--------
376
47
94
--------
1.0246
$0.47×2.18 = 1.0246$
55.180
+ 54.828
--------
110.008
$55.18 + 54.828 = 110.008$

3. 计算下列各题，能简算的要简算。
$6.86 - (2.19 + 1.86)$ $6.86 - (2.19 - 1.86)$
$0.38×10.1$ $0.38×9.9$
$0.56 + 0.56×43 + 47×0.56$ $0.56 + 5.6×43 + 0.47×56$

6.86 - (2.19 + 1.86)
=6.86 - 1.86 - 2.19
=5 - 2.19
=2.81
6.86 - (2.19 - 1.86)
=6.86 - 2.19 + 1.86
=6.86 + 1.86 - 2.19
=8.72 - 2.19
=6.53
0.38×10.1
=0.38×(10 + 0.1)
=0.38×10 + 0.38×0.1
=3.8 + 0.038
=3.838
0.38×9.9
=0.38×(10 - 0.1)
=0.38×10 - 0.38×0.1
=3.8 - 0.038
=3.762
0.56 + 0.56×43 + 47×0.56
=0.56×(1 + 43 + 47)
=0.56×91
=50.96
0.56 + 5.6×43 + 0.47×56
=0.56 + 0.56×430 + 0.56×47
=0.56×(1 + 430 + 47)
=0.56×478
=267.68