简便运算题1/7+2/7+3/7+4/7+.+18/7+19/7+20/7 100/(100/99)/(99/98)./

问题描述:

简便运算题1/7+2/7+3/7+4/7+.+18/7+19/7+20/7 100/(100/99)/(99/98)./(4/3)/(3/2)/(2/1)
1个回答 分类:数学 2014-10-18

问题解答:

我来补答
1/7+2/7+3/7+4/7+.+18/7+19/7+20/7
=1/7×(1+2+3+4+……+18+19+20)
=1/7×(1+20)×20÷2
=1/7×21×10
=30
100/(100/99)/(99/98)./(4/3)/(3/2)/(2/1)
=100×99/100×98/99×……×3/4×2/3×1/2
=1
 
 
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