一、口算。
$63 + 8 =$ $80 - 8 =$ $78 + 8 - 50 =$
$86 - 7 =$ $43 + 40 =$ $92 - 70 - 7 =$
$47 + 5 =$ $67 - 9 =$ $20 + 65 - 9 =$
$31 - 9 =$ $5 + 76 =$ $65 - 20 - 6 =$
$6 + 38 =$ $57 - 30 =$ $25 + 60 + 7 =$
$63 - 6 =$ $61 + 30 =$ $58 - 9 + 40 =$
$66 + 4 =$ $23 - 5 =$ $54 - 9 - 6 =$
$76 - 40 =$ $44 + 7 =$ $70 + 4 - 30 =$
$5 + 18 =$ $64 - 5 =$ $87 - 70 + 8 =$
$74 - 7 =$ $33 + 20 =$ $23 + 40 - 5 =$

一、71 72 36
79 83 15
52 58 76
22 81 39
44 27 92
57 91 89
70 18 39
36 51 44
23 59 25
67 53 58

二、()里应填几?
$( ) + 9 = 20$ $2 + ( ) = 31$ $( ) - 5 = 55$
$( ) + 30 = 51$ $9 + ( ) = 70$ $( ) - 50 = 45$
$( ) + 6 = 86$ $20 + ( ) = 90$ $( ) - 8 = 16$

二、11 29 60
21 61 95
80 70 24