一、口算。
$49 + 61 =$ $420 \div 70 =$ $600 \times 60 =$
$550 \div 50 =$ $32 \times 30 =$ $66 - 42 =$
$500 \times 20 =$ $990 \div 9 =$ $120 \times 7 =$
$147 \div 7 =$ $310 \times 60 =$ $260 + 240 =$
$418 \times 2 =$ $100 - 57 =$ $279 \div 9 =$
$29 + 43 =$ $720 \div 80 =$ $27 \times 30 =$
$500 \div 10 =$ $260 + 90 =$ $430 - 270 =$
$73 - 25 =$ $240 \div 20 =$ $300 \div 60 =$
$750 \div 5 =$ $360 \times 2 =$ $80 + 150 =$
$92 - 39 =$ $400 \div 5 =$ $17 \times 60 =$

周四
一、110 6 36000
11 960 24
10000 110 840
21 18600 500
836 43 31
72 9 810
50 350 160
48 12 5
150 720 230
53 80 1020

二、计算下面各题。
$(216 + 48) \times 35 - 1500$ $37 \times [(365 + 135) \div 25]$ $(17 \times 58 - 397) \div 31$

二、7740 740 19