一、口算。
$70 + 20 =$
$4 + 58 =$
$2 + 15 + 20 =$
$5 + 57 =$
$69 - 41 =$
$55 - 3 - 22 =$
$52 - 6 =$
$37 + 6 =$
$23 + 70 - 63 =$
$62 + 30 =$
$55 - 50 =$
$12 - 9 + 68 =$
$91 - 7 =$
$68 + 7 =$
$75 + 7 - 12 =$
$48 + 2 =$
$88 - 26 =$
$35 - 23 + 16 =$
$71 + 17 =$
$64 - 6 =$
$66 + 22 - 80 =$
$47 - 25 =$
$27 + 11 =$
$33 - 13 + 18 =$
$33 + 44 =$
$76 - 13 =$
$67 + 7 - 50 =$
$88 - 36 =$
$18 + 9 =$
$59 - 16 + 15 =$

70+20=90
4+58=62
2+15+20=37
5+57=62
69-41=28
55-3-22=30
52-6=46
37+6=43
23+70-63=30
62+30=92
55-50=5
12-9+68=71
91-7=84
68+7=75
75+7-12=70
48+2=50
88-26=62
35-23+16=28
71+17=88
64-6=58
66+22-80=8
47-25=22
27+11=38
33-13+18=38
33+44=77
76-13=63
67+7-50=24
88-36=52
18+9=27
59-16+15=58

二、找规律，填一填。
1.
2.

1. 38 43
2. 56 36