一、口算。
2 + 9 =
28 + 3 =
68 + 4 =
35 + 6 =
91 - 8 =
12 - 7 =
78 - 50 =
58 + 6 =
6 + 15 =
56 + 20 =
41 - 30 =
85 - 6 =
83 - 6 =
45 + 5 =
69 + 30 =
7 + 26 =
47 - 9 =
53 - 50 =
79 - 20 =
22 + 60 =
17 + 70 =
45 + 8 =
80 - 50 =
74 - 20 =
37 - 9 =
20 + 38 =
62 + 8 =
34 + 9 =
73 - 5 =
50 - 20 =

一、11 31 72
41 83 5
28 64 21
76 11 79
77 50 99
33 38 3
59 82 87
53 30 54
28 58 70
43 68 30

二、给下面的算式排排队。(填序号)

()＜()＜()＜()＜()

二、⑤ ③ ① ②
④