一、口算。
$30 + 6 =$ $13 - 7 =$ $10 + 70 =$
$69 - 60 =$ $5 + 9 =$ $8 + 2 =$
$4 + 90 =$ $50 - 30 =$ $73 - 3 =$
$91 - 1 =$ $50 + 40 =$ $4 + 8 =$
$30 + 5 =$ $14 - 5 =$ $12 - 6 =$
$59 - 50 =$ $9 + 40 =$ $8 + 60 =$
$80 + 8 =$ $8 + 3 =$ $16 - 8 =$
$66 - 60 =$ $15 - 8 =$ $70 + 3 =$
$4 + 70 =$ $9 + 20 =$ $77 - 7 =$
$92 - 90 =$ $80 - 40 =$ $7 + 9 =$

一、36 6 80
9 14 10
94 20 70
90 90 12
35 9 6
9 49 68
88 11 8
6 7 73
74 29 70
2 40 16

二、在$□$里填合适的数。
$□ - 3 = 80$ $□ + 30 = 90$ $□ - 9 = 90$
$□ + 30 = 36$ $□ - 20 = 60$ $5 + □ = 55$
$65 - □ = 60$ $□ + 9 = 49$ $70 - □ = 20$

二、83 60 99
6 80 50
5 40 50