一、口算。
$12 - 8 =$ $65 - 5 =$ $20 + 50 + 10 =$
$5 + 6 =$ $40 - 40 =$ $83 - 3 + 8 =$
$37 - 30 =$ $40 + 3 =$ $65 - 60 + 9 =$
$14 - 4 =$ $17 - 10 =$ $3 + 7 - 4 =$
$13 - 8 =$ $6 + 50 =$ $4 + 8 - 5 =$
$6 + 7 =$ $24 - 20 =$ $43 - 40 + 12 =$
$10 + 20 =$ $20 + 70 =$ $70 - 30 + 50 =$
$15 - 8 =$ $57 - 50 =$ $12 - 3 + 2 =$
$19 - 10 =$ $70 + 7 =$ $42 - 2 + 7 =$
$17 - 8 =$ $8 + 50 =$ $57 - 50 + 6 =$

一、4 60 80
11 0 88
7 43 14
10 7 6
5 56 7
13 4 15
30 90 90
7 7 11
9 77 47
9 58 13

二、填表。

二、66 28 70
50 8 30