1. 直接写出得数。
1.4 + 0.78 =
1.75 ÷ 50 =
32 ÷ 80 =
108 ÷ 9 × 3 =
4.68 - 3.7 =
6.75 × 4 =
0.24 ÷ 6 =
40 × 50 ÷ 400 =
4.2 ÷ 30 =
40 ÷ 800 =
8.1 - 1.8 =
270 ÷ (9 × 6) =
5.5 ÷ 55 =
0.36 + 1.4 =
4.2 ÷ 70 =
8.35 + 7.85 + 4.65 =
1.2 × 9 =
0.11 × 8 =
65 ÷ 100 =
3.6 - 0.13 - 0.77 =
0.84 ÷ 42 =
6.6 - 0.82 =
3.5 - 0.53 =
17.8 - 8.9 - 4.8 =
10.2 - 1.2 =
2.8 × 60 =
7.5 ÷ 75 =
54 ÷ 27 ÷ 20 =
3.6 × 30 =
7.2 ÷ 80 =
4.1 - 0.59 =
3.25 + 7.5 + 1.75 =

1. 2.18 0.035 0.4 36
0.98 27 0.04 5
0.14 0.05 6.3 5
0.1 1.76 0.06 20.85
10.8 0.88 0.65 2.7
0.02 5.78 2.97 4.1
9 168 0.1 0.1
108 0.09 3.51 12.5

2. 计算下面各题，怎样简便就怎样计算。
$125÷ 5× 8-20$
$87× 99$
$469+180÷ 6× 30$
$68× 101-68$
$16× (75-25)÷ 40$
$[250-(78+82)]× 16$

2. 180 8613 1369
6800 20 1440

四位数2□7□既是3的倍数，又有因数5，这个四位数可能是多少？写出所有可能。

这个四位数可能是 2175,2475,2775,2070,2370,2670,2970。