这些题有简便方法吗？1、4005 -150 x 17 2、404 / [202 x (315-305)]

1、4000-150×(10+7)+5
=4000-1500-1050+5
=1455

2、404 / 202 /(315-305)
=2/10
=1/5

4005-150*17
=(150*30-150*3-45)-(150*20-150*3)
=150*(30-20)-45
=1500-45
=1455

404/[202*(315-305)]
=404/202*1/(315-305)
=2*1/10
=1/5

1.
4005 -150 x 17 2
=5*801-150 x 17 2
=5*3*267-15*10*172
=15*(267-1720)
=-15*1453
=-21795

404 / [202 x (315-305)]
=202*2/202*10
=2/10
=0.2

楼主没有打空格,害我把17看成172,我说呢,啷个儿这么复杂,再做
4005 -150 x 17
==4000+5-150 x (20-3)
=4000-3000+450+5
=1000+455
=1455

1.4005 -150 x 17 2=4005/15-10*172=267-1720
=67-1520=1453
2.404 / [202 x (315-305)]=404/202/10=0.2

已经很简便了