Toán Lớp 6: Tính :
B= 3/9 . 8/9 . 15/16 . … . 399/400
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Toán Lớp 6: Tính :
B= 3/9 . 8/9 . 15/16 . … . 399/400
Comments ( 2 )
$\dfrac{3}{4}$ . $\dfrac{8}{9}$ . … . $\dfrac{399}{400}$
$\text{= $\dfrac{1.3}{2.2}$ . $\dfrac{2.4}{3.3}$ . … . $\dfrac{19.21}{20.20}$}$
$\text{= $\dfrac{1.2. … .19}{2.3. …. 20 .}$ . $\dfrac{3.4. … 21}{2.3. … . 20}$}$
$\text{= $\dfrac{1}{20}$ . $\dfrac{21}{2}$}$
$\text{$\dfrac{21}{40}$}$
XIN CÂU TRẢ LỜI HAY NHẤT!
$\dfrac{3}{4}$ . $\dfrac{8}{9}$ …$\dfrac{399}{400}$
= $\dfrac{1.3}{2.2}$ . $\dfrac{2.4}{3.3}$ . …. . $\dfrac{19.21}{20.20}$
= $\dfrac{1. 2…. 19}{2. 3 ….. 20}$ . $\dfrac{3.4…21}{2.3…20}$
= $\dfrac{1}{20}$ . $\dfrac{21}{2}$
= $\dfrac{21}{40}$