一、口算。
$83 - 50 =$
$72 - 8 =$
$93 - 4 - 40 =$
$35 + 40 =$
$26 + 60 =$
$71 - 50 + 20 =$
$16 - 7 =$
$82 - 6 =$
$92 - 8 + 7 =$
$3 + 59 =$
$4 + 8 =$
$32 + 60 - 4 =$
$47 - 30 =$
$42 - 4 =$
$72 - 9 - 5 =$
$54 + 6 =$
$50 + 49 =$
$9 + 21 + 15 =$
$70 - 70 =$
$63 - 5 =$
$69 - 60 + 79 =$
$59 + 6 =$
$40 + 50 =$
$36 + 9 - 20 =$
$24 - 10 =$
$42 - 6 =$
$35 - 8 + 20 =$
$23 + 40 =$
$14 + 8 =$
$18 + 9 + 30 =$

一、33 64 49
75 86 41
9 76 91
62 12 88
17 38 58
60 99 45
0 58 88
65 90 25
14 36 47
63 22 57

二、在（）里填合适的数。
$73 - ($ ) $= 43$
$57 - ($ ) $= 37$
$40 + ($ ) $= 85$
$78 - ($ ) $= 69$
$($ ) $+ 5 = 54$
$46 - ($ ) $= 26$
$($ ) $- 5 = 55$
$80 - ($ ) $= 72$
$42 + ($ ) $= 48$

二、30 20 45
9 49 20
60 8 6