一、口算。
4.6 - 2.5 =
58 + 15 =
27 × 20 =
156 ÷ 3 =
0.4 × 6 =
7.5 + 5.5 =
1.8 × 5 =
532 - 122 =
9.65 ÷ 10 =
4.3 - 3.4 =
10.3 × 100 =
1.88 + 4.71 =
9.6 ÷ 4 =
14 ÷ 35 =
0.774 × 10 =
215 × 6 =
5.08 + 2.02 =
0.16 ÷ 8 =
0.108 ÷ 2 =
1.32 × 5 =
8.3 × 20 =
2.07 × 60 =
6.4 ÷ 32 =
15.6 ÷ 3 =
24 ÷ 15 =
2.7 × 300 =
150 ÷ 75 =
0.55 × 4 =
2.02 - 1.99 =
1.54 ÷ 2 =

4.6 - 2.5 = 2.1
58 + 15 = 73
27 × 20 = 540
156 ÷ 3 = 52
0.4 × 6 = 2.4
7.5 + 5.5 = 13
1.8 × 5 = 9
532 - 122 = 410
9.65 ÷ 10 = 0.965
4.3 - 3.4 = 0.9
10.3 × 100 = 1030
1.88 + 4.71 = 6.59
9.6 ÷ 4 = 2.4
14 ÷ 35 = 0.4
0.774 × 10 = 7.74
215 × 6 = 1290
5.08 + 2.02 = 7.1
0.16 ÷ 8 = 0.02
0.108 ÷ 2 = 0.054
1.32 × 5 = 6.6
8.3 × 20 = 166
2.07 × 60 = 124.2
6.4 ÷ 32 = 0.2
15.6 ÷ 3 = 5.2
24 ÷ 15 = 1.6
2.7 × 300 = 810
150 ÷ 75 = 2
0.55 × 4 = 2.2
2.02 - 1.99 = 0.03
1.54 ÷ 2 = 0.77

二、先将表格补充完整，再填空。
1. 已知姐姐比弟弟大8岁。
|弟弟/岁|1|2|3|4|…|n|
|姐姐/岁|1+8||||…||
当$n=12$时，姐姐的年龄是()岁。
2.
|桌子的数量/张|1|2|3|…|m|
|可以坐的人数||||…||
若用$y$表示$m$张桌子可以坐的人数，则当$y=36$时，桌子的数量是()张。

1. $2+8$ $3+8$ $4+8$ $n+8$ 20
2. 6 12 18 $6m$ 6