一、算一算,比一比,在每组得数大的算式后面画“√”。
$\left\{\begin{array}{l} 85+15+75÷5□\\ 85+(15+75)÷5□\end{array} \right. $
$\left\{\begin{array}{l} 36+14×12+26□\\ (36+14)×(12+26)□\end{array} \right. $
$\left\{\begin{array}{l} (650-50)÷(20+30)□\\ (650-50)÷20+30□\end{array} \right. $
$\left\{\begin{array}{l} 225-(46+14)÷15□\\ [225-(46+14)]÷15□\end{array} \right. $
$\left\{\begin{array}{l} 100-120÷4+20□\\ 100-120÷(4+20)□\end{array} \right. $
$\left\{\begin{array}{l} (300÷5+15)×3□\\ 300÷(5+15×3)□\end{array} \right. $
$\left\{\begin{array}{l} 180÷(36÷12+6)□\\ 180÷[36÷(12+6)]□\end{array} \right. $
$\left\{\begin{array}{l} (700-232)÷6×4□\\ (700-232)÷(6×4)□\end{array} \right. $

二、计算下面各题。
$840÷40+400÷20$
$350÷25+24×13$
$296+(84+12)×75$
$600-(697÷41+274)$
$891÷(684-21×31)$
$(128-84)×30-170$
$600-(130+35×5)$
$(360-420÷21)×4$
$(817-17×21)÷23$
$840÷[210÷(720÷24)]$
$36×[450÷(54-24)]$
$(382+464)÷(46-28)$
$868÷(98-91)÷31$
$330÷[64-(84-42)]$
$245-(192+280÷35)$
$23×[165-(49+26)]$

41 326 7496 309 27 1150 295 1360 20 120 540 47 4 15 45 2070

1. $840÷40 + 400÷20$
= $21 + 20$
= $41$
2. $350÷25 + 24×13$
= $14 + 312$
= $326$
3. $296 + (84 + 12)×75$
= $296 + 96×75$
= $296 + 7200$
= $7496$
4. $600 - (697÷41 + 274)$
= $600 - (17 + 274)$
= $600 - 291$
= $309$
5. $891÷(684 - 21×31)$
= $891÷(684 - 651)$
= $891÷33$
= $27$
6. $(128 - 84)×30 - 170$
= $44×30 - 170$
= $1320 - 170$
= $1150$
7. $600 - (130 + 35×5)$
= $600 - (130 + 175)$
= $600 - 305$
= $295$
8. $(360 - 420÷21)×4$
= $(360 - 20)×4$
= $340×4$
= $1360$
9. $(817 - 17×21)÷23$
= $(817 - 357)÷23$
= $460÷23$
= $20$
10. $840÷[210÷(720÷24)]$
= $840÷[210÷30]$
= $840÷7$
= $120$
11. $36×[450÷(54 - 24)]$
= $36×[450÷30]$
= $36×15$
= $540$
12. $(382 + 464)÷(46 - 28)$
= $846÷18$
= $47$
13. $868÷(98 - 91)÷31$
= $868÷7÷31$
= $124÷31$
= $4$
14. $330÷[64 - (84 - 42)]$
= $330÷[64 - 42]$
= $330÷22$
= $15$
15. $245 - (192 + 280÷35)$
= $245 - (192 + 8)$
= $245 - 200$
= $45$
16. $23×[165 - (49 + 26)]$
= $23×[165 - 75]$
= $23×90$
= $2070$