奥数简便运算一,3.6*31又2/5+43.9*6又2/5+6二,（81.4+1/6+1/4+1/5）/（1/6+1/4+1/5）三,51又2/3除以5/3+71又3/4除以7/4+91又4/5除以9/5四,6又7/10*121+444除以40/99+67*21.2五,（4又1/19-1/17）*（1/7+1/8+1/9）-4*（1/7-1/8+1/9）
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奥数简便运算一,3.6*31又2/5+43.9*6又2/5+6二,（81.4+1/6+1/4+1/5）/（1/6+1/4+1/5）三,51又2/3除以5/3+71又3/4除以7/4+91又4/5除以9/5四,6又7/10*121+444除以40/99+67*21.2五,（4又1/19-1/17）*（1/7+1/8+1/9）-4*（1/7-1/8+1/9）
奥数简便运算
一,3.6*31又2/5+43.9*6又2/5+6
二,（81.4+1/6+1/4+1/5）/（1/6+1/4+1/5）
三,51又2/3除以5/3+71又3/4除以7/4+91又4/5除以9/5
四,6又7/10*121+444除以40/99+67*21.2
五,（4又1/19-1/17）*（1/7+1/8+1/9）-4*（1/7-1/8+1/9）+（1/7+1/8+1/9）*（1/17-1/19）
奥数简便运算一,3.6*31又2/5+43.9*6又2/5+6二,（81.4+1/6+1/4+1/5）/（1/6+1/4+1/5）三,51又2/3除以5/3+71又3/4除以7/4+91又4/5除以9/5四,6又7/10*121+444除以40/99+67*21.2五,（4又1/19-1/17）*（1/7+1/8+1/9）-4*（1/7-1/8+1/9）
一,3.6*31又2/5+43.9*6又2/5+6
=3.6*(31+2/5)+43.9*(6+2/)+6
=3.6*31+3.6*2/5+43.9*6+43.9*2/5+6
=3.6*30+3.6+(3.6+43.9)*2/5+44.9*6
=108+3.6+47.5*2/5+(45-0.1)*6
=108+3.6+19+270-0.6
=108+19+270+3
=400
二,（81.4+1/6+1/4+1/5）/（1/6+1/4+1/5）
=81.4/（1/6+1/4+1/5） +（1/6+1/4+1/5） /（1/6+1/4+1/5）
=81.4/[(10+15+12)/60]+1
=81.4*60/37+1
=132+1
=133
三,51又2/3除以5/3+71又3/4除以7/4+91又4/5除以9/5
=(50+5/3)/(5/3)+(70+7/4)/(7/4)+(90+9/5)/(9/5)
=30+1+40+1+50+1
=123
四,6又7/10*121+444除以40/99+67*21.2
=6.7*121+6.7*212+444*99/40
=6.7*333+333*3.3
=333*(6.7+3.3)
=3330
五,（4又1/19-1/17）*（1/7+1/8+1/9）-4*（1/7-1/8+1/9）+（1/7+1/8+1/9）*（1/17-1/19）
=(4+1/19-1/17)*（1/7+1/8+1/9）+（1/7+1/8+1/9）*（1/17-1/19）- 4*（1/7-1/8+1/9）
=(1/7+1/8+1/9)(4+1/19-1/17+1/17-1/19)- 4*（1/7-1/8+1/9）
=4*(1/7+1/8+1/9)- 4*（1/7-1/8+1/9）
=4*(1/7+1/8+1/9-1/7+1/8-1/9)
=4*1/4
=1
一，3.6*31又2/5+43.9*6又2/5+6
=3.6*31.4+43.9*6.4+6
=[10-6.4]*31.4+43.9*6.4+6
=314-6.4*31.4+43.9*6.4+6
=320+6.4[43.9-31.4]
=320+6.4*12.5
=320+0.8*8*12.5
=320+0.8*100
=400
全部展开
一，3.6*31又2/5+43.9*6又2/5+6
=3.6*31.4+43.9*6.4+6
=[10-6.4]*31.4+43.9*6.4+6
=314-6.4*31.4+43.9*6.4+6
=320+6.4[43.9-31.4]
=320+6.4*12.5
=320+0.8*8*12.5
=320+0.8*100
=400
二，（81.4+1/6+1/4+1/5）/（1/6+1/4+1/5）
=81.4/[1/6+1/4+1/5]+1
=81.4*60/[10+15+12]+1
=81.4*60/37+1
=[74+7.4]*60/37+1
=74*60/37+7.4*60/37+1
=120+12+1
=133
三，51又2/3除以5/3+71又3/4除以7/4+91又4/5除以9/5
=[51+2/3]*3/5+[71+3/4]*4/7+[91+4/5]*5/9
=51*3/5+2/5+71*4/7+3/7+91*5/9+4/9
=[50+1]*3/5+[70+1]*4/7+[90+1]*5/9+2/5+3/7+4/9
=30+3/5+40+4/7+50+5/9+2/5+3/7+4/9
=120+1+1+1
=123
四，6又7/10*121+444除以40/99+67*21.2
=67/10*11*11+444*99/40+67*21.2
=6.7*11*11+11.1*99+67*21.2
=6.7[121+212]+11.1*99
=6.7*333+33.3*33
=33.3[67+33]
=33.3*100
=3330
五，（4又1/19-1/17）*（1/7+1/8+1/9）-4*（1/7-1/8+1/9）+（1/7+1/8+1/9）*（1/17-1/19）
=(4+1/19-1/17)*（1/7+1/8+1/9）+（1/7+1/8+1/9）*（1/17-1/19）- 4*（1/7-1/8+1/9）
=(1/7+1/8+1/9)(4+1/19-1/17+1/17-1/19)- 4*（1/7-1/8+1/9）
=4*(1/7+1/8+1/9)- 4*（1/7-1/8+1/9）
=4*(1/7+1/8+1/9-1/7+1/8-1/9)
=4*1/4
=1
收起
一，3.6*31又2/5+43.9*6又2/5+6
=3.6*(31+2/5)+43.9*(6+2/)+6
=3.6*31+3.6*2/5+43.9*6+43.9*2/5+6
=3.6*30+3.6+(3.6+43.9)*2/5+44.9*6
=108+3.6+47.5*2/5+(45-0.1)*6
=108+3.6+19+270-0.6
全部展开
一，3.6*31又2/5+43.9*6又2/5+6
=3.6*(31+2/5)+43.9*(6+2/)+6
=3.6*31+3.6*2/5+43.9*6+43.9*2/5+6
=3.6*30+3.6+(3.6+43.9)*2/5+44.9*6
=108+3.6+47.5*2/5+(45-0.1)*6
=108+3.6+19+270-0.6
=108+19+270+3
=400
二，（81.4+1/6+1/4+1/5）/（1/6+1/4+1/5）
=81.4/（1/6+1/4+1/5） +（1/6+1/4+1/5） /（1/6+1/4+1/5）
=81.4/[(10+15+12)/60]+1
=81.4*60/37+1
=132+1
=133
三，51又2/3除以5/3+71又3/4除以7/4+91又4/5除以9/5
=(50+5/3)/(5/3)+(70+7/4)/(7/4)+(90+9/5)/(9/5)
=30+1+40+1+50+1
=123
四，6又7/10*121+444除以40/99+67*21.2
=6.7*121+6.7*212+444*99/40
=6.7*333+333*3.3
=333*(6.7+3.3)
=3330
五，（4又1/19-1/17）*（1/7+1/8+1/9）-4*（1/7-1/8+1/9）+（1/7+1/8+1/9）*（1/17-1/19）
=(4+1/19-1/17)*（1/7+1/8+1/9）+（1/7+1/8+1/9）*（1/17-1/19）- 4*（1/7-1/8+1/9）
=(1/7+1/8+1/9)(4+1/19-1/17+1/17-1/19)- 4*（1/7-1/8+1/9）
=4*(1/7+1/8+1/9)- 4*（1/7-1/8+1/9）
=4*(1/7+1/8+1/9-1/7+1/8-1/9)
=4*1/4
=1
一、3.6*31又2/5+43.9*6又2/5+6
=3.6*31.4+43.9*6.4+6
=[10-6.4]*31.4+43.9*6.4+6
=314-6.4*31.4+43.9*6.4+6
=320+6.4[43.9-31.4]
=320+6.4*12.5
=320+0.8*8*12.5
=320+0.8*100
=400
二、（81.4+1/6+1/4+1/5）/（1/6+1/4+1/5）
=81.4/[1/6+1/4+1/5]+1
=81.4*60/[10+15+12]+1
=81.4*60/37+1
=[74+7.4]*60/37+1
=74*60/37+7.4*60/37+1
=120+12+1
=133
三、51又2/3除以5/3+71又3/4除以7/4+91又4/5除以9/5
=[51+2/3]*3/5+[71+3/4]*4/7+[91+4/5]*5/9
=51*3/5+2/5+71*4/7+3/7+91*5/9+4/9
=[50+1]*3/5+[70+1]*4/7+[90+1]*5/9+2/5+3/7+4/9
=30+3/5+40+4/7+50+5/9+2/5+3/7+4/9
=120+1+1+1
=123
四、67/10*121+444除以40/99+67*21.2
=67/10*11*11+444*99/40+67*21.2
=6.7*11*11+11.1*99+67*21.2
=6.7[121+212]+11.1*99
=6.7*333+33.3*33
=33.3[67+33]
=33.3*100
=3330
五、（4又1/19-1/17）*（1/7+1/8+1/9）-4*（1/7-1/8+1/9）+（1/7+1/8+1/9）*（1/17-1/19）
=(4+1/19-1/17)*（1/7+1/8+1/9）+（1/7+1/8+1/9）*（1/17-1/19）- 4*（1/7-1/8+1/9）
=(1/7+1/8+1/9)(4+1/19-1/17+1/17-1/19)- 4*（1/7-1/8+1/9）
=4*(1/7+1/8+1/9)- 4*（1/7-1/8+1/9）
=4*(1/7+1/8+1/9-1/7+1/8-1/9)
=4*1/4
=1
基本在04年的奥赛书上都有解析。写的我累死了！
收起
难,,真不容易,,分,,基本上是冲着难题来的,可是惭愧,不会,,,,不过,还是想发发言,,说说话,,
但愿楼主学有富车,,,
这些题我看楼主还是自己做为好，这样才能提高计算效率。
一，3.6*31又2/5+43.9*6又2/5+6
=3.6*(31+2/5)+43.9*(6+2/)+6
=3.6*31+3.6*2/5+43.9*6+43.9*2/5+6
=3.6*30+3.6+(3.6+43.9)*2/5+44.9*6
=108+3.6+47.5*2/5+(45-0.1)*6
=108+3.6+19+270-0.6
全部展开
一，3.6*31又2/5+43.9*6又2/5+6
=3.6*(31+2/5)+43.9*(6+2/)+6
=3.6*31+3.6*2/5+43.9*6+43.9*2/5+6
=3.6*30+3.6+(3.6+43.9)*2/5+44.9*6
=108+3.6+47.5*2/5+(45-0.1)*6
=108+3.6+19+270-0.6
=108+19+270+3
=400
二，（81.4+1/6+1/4+1/5）/（1/6+1/4+1/5）
=81.4/（1/6+1/4+1/5） +（1/6+1/4+1/5） /（1/6+1/4+1/5）
=81.4/[(10+15+12)/60]+1
=81.4*60/37+1
=132+1
=133
三，51又2/3除以5/3+71又3/4除以7/4+91又4/5除以9/5
=(50+5/3)/(5/3)+(70+7/4)/(7/4)+(90+9/5)/(9/5)
=30+1+40+1+50+1
=123
四，6又7/10*121+444除以40/99+67*21.2
=6.7*121+6.7*212+444*99/40
=6.7*333+333*3.3
=333*(6.7+3.3)
=3330
五，（4又1/19-1/17）*（1/7+1/8+1/9）-4*（1/7-1/8+1/9）+（1/7+1/8+1/9）*（1/17-1/19）
=(4+1/19-1/17)*（1/7+1/8+1/9）+（1/7+1/8+1/9）*（1/17-1/19）- 4*（1/7-1/8+1/9）
=(1/7+1/8+1/9)(4+1/19-1/17+1/17-1/19)- 4*（1/7-1/8+1/9）
=4*(1/7+1/8+1/9)- 4*（1/7-1/8+1/9）
=4*(1/7+1/8+1/9-1/7+1/8-1/9)
=4*1/4
=1
一、3.6*31又2/5+43.9*6又2/5+6
=3.6*31.4+43.9*6.4+6
=[10-6.4]*31.4+43.9*6.4+6
=314-6.4*31.4+43.9*6.4+6
=320+6.4[43.9-31.4]
=320+6.4*12.5
=320+0.8*8*12.5
=320+0.8*100
=400
二、（81.4+1/6+1/4+1/5）/（1/6+1/4+1/5）
=81.4/[1/6+1/4+1/5]+1
=81.4*60/[10+15+12]+1
=81.4*60/37+1
=[74+7.4]*60/37+1
=74*60/37+7.4*60/37+1
=120+12+1
=133
三、51又2/3除以5/3+71又3/4除以7/4+91又4/5除以9/5
=[51+2/3]*3/5+[71+3/4]*4/7+[91+4/5]*5/9
=51*3/5+2/5+71*4/7+3/7+91*5/9+4/9
=[50+1]*3/5+[70+1]*4/7+[90+1]*5/9+2/5+3/7+4/9
=30+3/5+40+4/7+50+5/9+2/5+3/7+4/9
=120+1+1+1
=123
四、67/10*121+444除以40/99+67*21.2
=67/10*11*11+444*99/40+67*21.2
=6.7*11*11+11.1*99+67*21.2
=6.7[121+212]+11.1*99
=6.7*333+33.3*33
=33.3[67+33]
=33.3*100
=3330
五、（4又1/19-1/17）*（1/7+1/8+1/9）-4*（1/7-1/8+1/9）+（1/7+1/8+1/9）*（1/17-1/19）
=(4+1/19-1/17)*（1/7+1/8+1/9）+（1/7+1/8+1/9）*（1/17-1/19）- 4*（1/7-1/8+1/9）
=(1/7+1/8+1/9)(4+1/19-1/17+1/17-1/19)- 4*（1/7-1/8+1/9）
=4*(1/7+1/8+1/9)- 4*（1/7-1/8+1/9）
=4*(1/7+1/8+1/9-1/7+1/8-1/9)
=4*1/4
=1
收起