一、口算。
$73 - 37 =$ $11×40 =$ $324÷3 =$
$460÷5 =$ $84 - 26 =$ $23×20 =$
$470 - 400 =$ $96÷3 =$ $58 + 27 =$
$464÷8 =$ $81×30 =$ $140 - 60 =$
$90×50 =$ $36 + 37 =$ $800×5 =$
$69 + 41 =$ $54×7 =$ $692÷4 =$
$40×60 =$ $636÷2 =$ $21×40 =$
$800÷4 =$ $3×400 =$ $28÷14 =$
$100 - 54 =$ $44 + 38 =$ $210 - 90 =$
$25×6 =$ $674÷2 =$ $84÷3 =$

36 440 108
92 58 460
70 32 85
58 2430 80
4500 73 4000
110 378 173
2400 318 840
200 1200 2
46 82 120
150 337 28

二、计算下面各题。
$205÷41×68 + 135$ $(49×15 - 399)÷48$ $23×(264÷8) - 415$

475 7 344