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 =

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 ①⑤ ③

②＞④＞①＞⑤＞③