Tính nhanh: $\frac{108}{120}+\frac{104}{130}+\frac{98}{140}+\frac{90}{150}+\frac{80}{160}+\frac{68}{170}+\frac{54}{180}+\frac{38}{190}+\frac{1}{10}$
Tính nhanh: $\frac{108}{120}+\frac{104}{130}+\frac{98}{140}+\frac{90}{150}+\frac{80}{160}+\frac{68}{170}+\frac{54}{180}+\frac{38}{190}+\frac{1}{10}$
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$\begin{align} & \frac{108}{120}+\frac{104}{130}+\frac{98}{140}+\frac{90}{150}+\frac{80}{160}+\frac{68}{170}+\frac{54}{180}+\frac{38}{190}+\frac{1}{10} \\ & =\frac{9}{10}+\frac{4}{5}+\frac{7}{10}+\frac{3}{5}+\frac{1}{2}+\frac{2}{5}+\frac{3}{10}+\frac{1}{5}+\frac{1}{10} \\ & =\left( \frac{9}{10}+\frac{1}{10} \right)+\left( \frac{4}{5}+\frac{1}{5} \right)+\left( \frac{7}{10}+\frac{3}{10} \right)+\left( \frac{3}{5}+\frac{2}{5} \right)+\frac{1}{2} \\ & =1+1+1+1+\frac{1}{2}\\ & =4+\frac{1}{2} \\ &=\frac{9}{2} \\ \end{align}$
Xin hay nhất !
Neala
Giải thích các bước giải:
`108/120+104/130+98/140+90/150+80/160+68/170+54/180+38/190+1/10`
`=9/10+4/5+7/10+3/5+1/2+2/5+3/10+1/5+1/10`
`=(9/10+1/10)+(4/5+1/5)+(7/10+3/10)+(3/5+2/5)+1/2`
`=4+1/2`
`=9/2`