Toán 9/10 +1/90++1/72+1/56+1/42+1/30+1/20+1/12+1/6+1/2 08/07/2021 By Aubrey 9/10 +1/90++1/72+1/56+1/42+1/30+1/20+1/12+1/6+1/2
9/10+1/90+1/72+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 Trả lời
*Hình dưới: $\frac{9}{10}+$ $\frac{1}{90}+…+$ $\frac{1}{2}$ $=\frac{1}{2}+…+$ $\frac{1}{90}+$ $\frac{9}{10}$ $=\frac{1}{1.2}+…+$$\frac{1}{9.10}+$ $\frac{9}{10}$ $=1-\frac{1}{2}+…+$ $\frac{1}{9}-$ $\frac{1}{10}+$ $\frac{9}{10}$ $=1-\frac{1}{10}+$ $\frac{9}{10}$ $=\frac{9}{10}+$ $\frac{9}{10}$ $=\frac{9}{5}$ Trả lời
9/10+1/90+1/72+1/56+1/42+1/30+1/20+1/12+1/6+1/2
=(9/10+1/90+1/20+1/30)+(1/6+1/12+1/2)+(1/72+1/42+1/56)
=179/180+3/4+1/18
=(179/180+10/180)+3/4
=21/20+3/4
=21/20+15/20
=36/20=9/5
*Hình dưới:
$\frac{9}{10}+$ $\frac{1}{90}+…+$ $\frac{1}{2}$
$=\frac{1}{2}+…+$ $\frac{1}{90}+$ $\frac{9}{10}$
$=\frac{1}{1.2}+…+$$\frac{1}{9.10}+$ $\frac{9}{10}$
$=1-\frac{1}{2}+…+$ $\frac{1}{9}-$ $\frac{1}{10}+$ $\frac{9}{10}$
$=1-\frac{1}{10}+$ $\frac{9}{10}$
$=\frac{9}{10}+$ $\frac{9}{10}$
$=\frac{9}{5}$