一、口算。
70 + 7 =
93 - 90 =
9 + 9 =
78 - 8 =
30 + 9 =
13 - 6 =
50 + 8 =
12 - 3 =
80 + 10 =
17 - 9 =
4 + 60 =
23 - 20 =
5 + 6 =
67 - 60 =
80 + 3 =
76 - 70 =
70 - 60 =
13 - 4 =
3 + 8 =
46 - 40 =
10 + 10 =
90 - 40 =
5 + 40 =
97 - 90 =
6 + 30 =
11 - 5 =
5 + 8 =
27 - 20 =
3 + 50 =
88 - 80 =

周五
一、77 3 18
70 39 7
58 9 90
8 64 3
11 7 83
6 10 9
11 6 20
50 45 7
36 6 13
7 53 8

二、把下面的算式按得数从大到小的顺序排列。(填序号)

()＞()＞()＞()＞()

二、② ④ ① ⑤ ③