一、口算。
$73 - 70 =$
$50 + 6 =$
$15 - 8 =$
$6 + 8 =$
$20 - 10 =$
$9 + 50 =$
$83 - 80 =$
$10 + 3 =$
$22 - 20 =$
$30 + 20 =$
$17 - 9 =$
$3 + 90 =$
$73 - 3 =$
$40 + 40 =$
$11 - 7 =$
$2 + 70 =$
$14 - 5 =$
$5 + 6 =$
$95 - 5 =$
$7 + 50 =$
$60 - 50 =$
$60 + 9 =$
$80 - 20 =$
$7 + 5 =$
$15 - 7 =$
$9 + 40 =$
$78 - 8 =$
$5 + 8 =$
$94 - 90 =$
$50 + 8 =$

一、3 56 7
14 10 59
3 13 2
50 8 93
70 80 4
72 9 11
90 57 10
69 60 12
8 49 70
13 4 58

二、比一比，连一连。

二、