9/10 +1/90++1/72+1/56+1/42+1/30+1/20+1/12+1/6+1/2

0 bình luận về “9/10 +1/90++1/72+1/56+1/42+1/30+1/20+1/12+1/6+1/2”

1. 9/10+1/90+1/72+1/56+1/42+1/30+1/20+1/12+1/6+1/2

   =(9/10+1/90+1/20+1/30)+(1/6+1/12+1/2)+(1/72+1/42+1/56)

   =179/180+3/4+1/18

   =(179/180+10/180)+3/4

   =21/20+3/4

   =21/20+15/20

   =36/20=9/5

    

   Bình luận

2. *Hình dưới:

     $\frac{9}{10}+$ $\frac{1}{90}+…+$ $\frac{1}{2}$

   $=\frac{1}{2}+…+$ $\frac{1}{90}+$ $\frac{9}{10}$

   $=\frac{1}{1.2}+…+$$\frac{1}{9.10}+$ $\frac{9}{10}$

   $=1-\frac{1}{2}+…+$ $\frac{1}{9}-$ $\frac{1}{10}+$ $\frac{9}{10}$

   $=1-\frac{1}{10}+$ $\frac{9}{10}$

   $=\frac{9}{10}+$ $\frac{9}{10}$

   $=\frac{9}{5}$ 

   Bình luận