一、口算。
$56 + 19 =$ $83 - 40 =$ $58 + 23 =$
$66 - 24 =$ $62 + 28 =$ $35 - 18 =$
$24 + 46 =$ $70 - 34 =$ $20 + 74 =$
$73 - 27 =$ $50 - 45 =$ $41 - 15 =$
$27 + 27 =$ $49 + 16 =$ $18 + 79 =$
$78 - 50 =$ $88 - 59 =$ $52 - 47 =$
$29 + 55 =$ $55 + 37 =$ $46 + 40 =$
$51 - 39 =$ $80 - 23 =$ $94 - 52 =$
$17 + 28 =$ $45 + 27 =$ $46 + 32 =$
$73 - 45 =$ $64 - 18 =$ $67 - 36 =$

一、75 43 81
42 90 17
70 36 94
46 5 26
54 65 97
28 29 5
84 92 86
12 57 42
45 72 78
28 46 31

二、在$\square$里填合适的数。
$29\xrightarrow{+17}\square\xrightarrow{+46}\square\xrightarrow{-54}\square\xrightarrow{+35}\square\xrightarrow{-23}\square$
$70\xrightarrow{-46}\square\xrightarrow{+37}\square\xrightarrow{-38}\square\xrightarrow{+49}\square\xrightarrow{-54}\square$
$52\xrightarrow{+38}\square\xrightarrow{-44}\square\xrightarrow{+19}\square\xrightarrow{-26}\square\xrightarrow{+35}\square$

二、46 92 38 73 50
24 61 23 72 18
90 46 65 39 74