一、口算。
$8 + 75 =$ $82 - 50 =$ $21 - 2 + 70 =$
$3 + 33 =$ $39 + 20 =$ $75 + 6 - 50 =$
$2 + 57 =$ $58 - 9 =$ $26 + 4 + 5 =$
$66 - 9 =$ $20 + 17 =$ $99 - 80 + 3 =$
$20 + 55 =$ $62 - 20 =$ $85 + 6 - 8 =$
$77 - 9 =$ $34 + 9 =$ $72 - 7 - 20 =$
$6 + 87 =$ $92 - 40 =$ $50 + 18 + 6 =$
$87 - 70 =$ $74 + 8 =$ $70 - 50 + 13 =$
$70 + 15 =$ $63 - 50 =$ $5 + 89 - 90 =$
$45 - 6 =$ $86 + 4 =$ $47 - 10 - 8 =$

一、83 32 89
36 59 31
59 49 35
57 37 22
75 42 83
68 43 45
93 52 74
17 82 33
85 13 4
39 90 29

二、()里最大能填几?
$45 - ( ) ＞ 4$ $( ) + 50 ＜ 92$ $6 + ( ) ＜ 30$
$77 - ( ) ＞ 69$ $( ) + 5 ＜ 92$ $60 + ( ) ＜ 99$
$36 - ( ) ＞ 5$ $( ) + 7 ＜ 41$ $8 + ( ) ＜ 66$

二、40 41 23
7 86 38
30 33 57