问几道数学思考题(急 ⑴62又80/89×1/9⑵9又4/5+99又4/5+999又4/5+9999又4/5+4/5⑶2006÷2006又2006/2007⑷1×3+2×6+3×9+4×12+5×15/1×2+2×4+3×6+4×8+5×10⑸84又4/19×1.375+105又5/19×0.9⑹(1+1/2) ×(1
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![问几道数学思考题(急 ⑴62又80/89×1/9⑵9又4/5+99又4/5+999又4/5+9999又4/5+4/5⑶2006÷2006又2006/2007⑷1×3+2×6+3×9+4×12+5×15/1×2+2×4+3×6+4×8+5×10⑸84又4/19×1.375+105又5/19×0.9⑹(1+1/2) ×(1](/uploads/image/z/2740406-14-6.jpg?t=%E9%97%AE%E5%87%A0%E9%81%93%E6%95%B0%E5%AD%A6%E6%80%9D%E8%80%83%E9%A2%98%28%E6%80%A5+%E2%91%B462%E5%8F%8880%2F89%C3%971%2F9%E2%91%B59%E5%8F%884%2F5%EF%BC%8B99%E5%8F%884%2F5%EF%BC%8B999%E5%8F%884%2F5%EF%BC%8B9999%E5%8F%884%2F5%EF%BC%8B4%2F5%E2%91%B62006%C3%B72006%E5%8F%882006%2F2007%E2%91%B71%C3%973%EF%BC%8B2%C3%976%EF%BC%8B3%C3%979%EF%BC%8B4%C3%9712%EF%BC%8B5%C3%9715%2F1%C3%972%EF%BC%8B2%C3%974%EF%BC%8B3%C3%976%EF%BC%8B4%C3%978%EF%BC%8B5%C3%9710%E2%91%B884%E5%8F%884%2F19%C3%971.375%EF%BC%8B105%E5%8F%885%2F19%C3%970.9%E2%91%B9%281%EF%BC%8B1%2F2%29+%C3%97%281)
问几道数学思考题(急 ⑴62又80/89×1/9⑵9又4/5+99又4/5+999又4/5+9999又4/5+4/5⑶2006÷2006又2006/2007⑷1×3+2×6+3×9+4×12+5×15/1×2+2×4+3×6+4×8+5×10⑸84又4/19×1.375+105又5/19×0.9⑹(1+1/2) ×(1
问几道数学思考题(急
⑴62又80/89×1/9
⑵9又4/5+99又4/5+999又4/5+9999又4/5+4/5
⑶2006÷2006又2006/2007
⑷1×3+2×6+3×9+4×12+5×15/1×2+2×4+3×6+4×8+5×10
⑸84又4/19×1.375+105又5/19×0.9
⑹(1+1/2) ×(1-1/2) ×(1+1/3) ×(1-1/3) ×…×(1+1/100) ×(1-1/100)
⑺(1-1/2×1/2) ×(1-1/3×1/3) ×(1-1/4×1/4) ×…×(1-1/100×1/100)
问几道数学思考题(急 ⑴62又80/89×1/9⑵9又4/5+99又4/5+999又4/5+9999又4/5+4/5⑶2006÷2006又2006/2007⑷1×3+2×6+3×9+4×12+5×15/1×2+2×4+3×6+4×8+5×10⑸84又4/19×1.375+105又5/19×0.9⑹(1+1/2) ×(1
⑴62又80/89×1/9
=(63-9/89)*1/9
=63*1/9-9/89*1/9
=7-1/89
=6又88/89
⑵9又4/5+99又4/5+999又4/5+9999又4/5+4/5
=(9又4/5+1/5)+(99又4/5+1/5)+(999又4/5+1/5)+(9999又4/5+1/5)
=10+100+1000+10000
=11110
⑶2006÷2006又2006/2007
=2006/[(2006*2007+2006)/2007]
=2006/[2006*2008/2007]
=2006*[2007/(2006*2008)]
=(2006*2007)/(2006*2008)
=2007/2008
⑷1×3+2×6+3×9+4×12+5×15/1×2+2×4+3×6+4×8+5×10
=[1*3+2*(1*3)+3*(1*3)+4*(1*3)+5*(1*3)]/[1*2+2*(1*2)+3*(1*2)+4*(1*2)+5*(1*2)]
=[(1*3)*(1+2+3=4+5)]/[(1*2)*(1+2+3+4+5)]
=3/2
⑸84又4/19×1.375+105又5/19×0.9
=(21又1/19)*4*1.375+(21又1/19)*5*0.9
=21又1/19*5.5+21又1/19*4.5
=21又1/19*(5.5+4.5)
=21又1/19*10
=21*10+1/19*10
=210+10/19
=210又10/19
⑹(1+1/2) ×(1-1/2) ×(1+1/3) ×(1-1/3) ×…×(1+1/100) ×(1-1/100)
=1/2*1/2*4/3*2/3*.*101/100*99/100
=1/2*101/100
=101/200
⑺(1-1/2×1/2) ×(1-1/3×1/3) ×(1-1/4×1/4) ×…×(1-1/100×1/100)
=(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*(1+1/4)*(1-1/4)*.*(1+1/100)*(1-1/100)
=1/2*1/2*4/3*2/3*.*101/100*99/100
=1/2*101/100
=101/200
⑴62又80/89×1/9
=(63-9/89)*1/9
=7-1/89
=6又88/9
⑵9又4/5+99又4/5+999又4/5+9999又4/5+4/5
=(10-1/5)+(100-1/5)+(1000-1/5)+(10000-1/5)+4/5
=11110
⑶2006÷2006又2006/2007
=2006*2006...
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⑴62又80/89×1/9
=(63-9/89)*1/9
=7-1/89
=6又88/9
⑵9又4/5+99又4/5+999又4/5+9999又4/5+4/5
=(10-1/5)+(100-1/5)+(1000-1/5)+(10000-1/5)+4/5
=11110
⑶2006÷2006又2006/2007
=2006*2006/(2006+2006*2007)
=2006/(1+2007)
=1003/1004
⑷1×3+2×6+3×9+4×12+5×15/1×2+2×4+3×6+4×8+5×10
=(3+2*2*3+3*3*3+4*4*3+5*5*3)/(2+2*2*2+3*3*2+4*4*2+5*5*2)
=3(1+4+9+16+25)/2(1+4+9+16+25)
=3/2
⑸84又4/19×1.375+105又5/19×0.9
=(85-5/19)*1.375+(105+5/19)*0.9
=85*1.375-5/19*1.375+105*0.9+5/19*0.9
=85*11/8+94.5-5/19*0.475
=210.25
⑹(1+1/2) ×(1-1/2) ×(1+1/3) ×(1-1/3) ×…×(1+1/100) ×(1-1/100)
=3/2*1/2*4/3*2/3*……*101/100*99/100
=1/2*101/100
=101/200
⑺(1-1/2×1/2) ×(1-1/3×1/3) ×(1-1/4×1/4) ×…×(1-1/100×1/100)
=3/4*8/9*15/16*……*9999/10000
=3/2*1/2*4/3*2/3*……*101/100*99/100
=1/2*101/100
=101/200
收起
1.62又80/89×1/9
=(63-9/89)*1/9
=63*1/9-9/89*1/9
=7-1/89
=6又88/89
2.9又4/5+99又4/5+999又4/5+9999又4/5+4/5
=(10-1/5)+(100-1/5)+(1000-1/5)+(10000-1/5)+4/5
=11110
3...
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1.62又80/89×1/9
=(63-9/89)*1/9
=63*1/9-9/89*1/9
=7-1/89
=6又88/89
2.9又4/5+99又4/5+999又4/5+9999又4/5+4/5
=(10-1/5)+(100-1/5)+(1000-1/5)+(10000-1/5)+4/5
=11110
3.2006÷2006又2006/2007
=2006*2006/(2006+2006*2007)
=2006/(1+2007)
=1003/1004
4.1×3+2×6+3×9+4×12+5×15/1×2+2×4+3×6+4×8+5×10
=(3+2*2*3+3*3*3+4*4*3+5*5*3)/(2+2*2*2+3*3*2+4*4*2+5*5*2)
=3(1+4+9+16+25)/2(1+4+9+16+25)
=3/2
5.84又4/19×1.375+105又5/19×0.9
=(21又1/19)*4*1.375+(21又1/19)*5*0.9
=21又1/19*5.5+21又1/19*4.5
=21又1/19*(5.5+4.5)
=21又1/19*10
=21*10+1/19*10
=210+10/19
=210又10/19
6.(1+1/2) ×(1-1/2) ×(1+1/3) ×(1-1/3) ×…×(1+1/100) ×(1-1/100)
=3/2*1/2*4/3*2/3*……*101/100*99/100
=1/2*101/100
=101/200
7.(1-1/2×1/2) ×(1-1/3×1/3) ×(1-1/4×1/4) ×…×(1-1/100×1/100)
=(1+1/2)*(1-1/2)*(1+1/3)*(1-1/3)*(1+1/4)*(1-1/4)*......*(1+1/100)*(1-1/100)
=1/2*1/2*4/3*2/3*......*101/100*99/100
=1/2*101/100
=101/200
收起