1. 直接写出得数。(20☆)
0.9×0.5=
0.2×0.2=
85×0.01=
0.84×0.05=
10×0.1=
80×0.4=
36×0.3=
0.7×0.8=
1.8×0.5=
0.8×0.2=
50×0.12=
40×0.7=
1.5×0.04=
0.15×0.3=
7.8×0.5=
1.6×0.002=
0.5×0.8=
0.5×1.1=
0.54×0.5=
6.32×2=
100×0.25=
0.7×0.4=
13.8×7=
2.23×4=
0.12×40=
4.5×3=
0.3×0.31=
0.57×0.4=
1.2−0.8=
23.9+6.1=
1.2×4=
0.8×0.16=
7.8−6.5=
3.3×30=
9.85+0.5=
1.92×3=
2.4×0.8=
1.2×0.9=
11.8×0.2=
3.3×0.4=

1. 0.45 0.04 0.85 0.042
1 32 10.8 0.56
0.9 0.16 6 28
0.06 0.045 3.9 0.0032
0.4 0.55 0.27 12.64
25 0.28 96.6 8.92
4.8 13.5 0.093 0.228
0.4 30 4.8 0.128
1.3 99 10.35 5.76
1.92 1.08 2.36 1.32

2. 根据 $87 × 45 = 3915$，在下面的括号里填上合适的数。(16☆)
$391.5 = (\quad) × (\quad)$
$= (\quad) × (\quad)$
$39.15 = (\quad) × (\quad)$
$= (\quad) × (\quad)$
$3.915 = (\quad) × (\quad)$
$= (\quad) × (\quad)$
$0.3915 = (\quad) × (\quad)$
$= (\quad) × (\quad)$

2. 8.7×45 87×4.5
0.87×45 87×0.45
8.7×0.45 87×0.045
0.87×0.45 87×0.0045
（答案不唯一）

3. 请根据前三题的得数,找出规律,直接写出后面两题的得数。(12☆)
(1) $0.1+0×0.9=0.1$
$0.2+1×0.9=1.1$
$0.3+12×0.9=11.1$
$0.4+123×0.9=(\quad)$
$0.5+1234×0.9=(\quad)$
(2) $99×99=9801$
$999×999=998001$
$9999×9999=99980001$
$99999×99999=(\quad)$
$999999×999999=(\quad)$

3. (1)111.1 1111.1
(2)9999800001 999998000001

4. 把$1.895×(\blacktriangle +0.3)$算成$1.895× \blacktriangle +0.3$，计算的结果与正确的结果相差多少？(4☆)
用时：分钟 ★共得：☆/100 ☆

4. $1.895×(\blacktriangle +0.3)= 1.895×\blacktriangle +1.895×0.3$
$1.895×\blacktriangle +1.895×0.3-(1.895×\blacktriangle +0.3)$
$= 0.2685$