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a) \(\left(\frac{3}{5}.\frac{5}{3}\right).\frac{8}{27}\)
= \(1.\frac{8}{27}\)
=\(\frac{8}{27}\)
b) \(\frac{7}{19}.\left(\frac{1}{3}.\frac{2}{3}\right)\)
= \(\frac{7}{19}.\frac{2}{9}\)
=\(\frac{14}{81}\)
Không biết có đúng không? Tick mình nha !
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\(\frac{7}{19}\)x\(\frac{1}{3}\)+\(\frac{7}{19}\)x\(\frac{2}{3}\)=\(\frac{7}{19}\)x(\(\frac{1}{3}\)+\(\frac{2}{3}\))=\(\frac{7}{19}\)x1=\(\frac{7}{19}\)
\(\frac{7}{19}\)x \(\frac{1}{3}\)x \(\frac{7}{19}\)x \(\frac{2}{3}\)
= \(\frac{7}{19}\)x (\(\frac{1}{3}\)+ \(\frac{2}{3}\))
= \(\frac{7}{19}\)x 1
= \(\frac{7}{19}\)
Chúc bạn học tốt!
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\(\frac{1}{5}\cdot\frac{1}{7}+\frac{4}{5}+\frac{1}{5}\cdot\frac{12}{7}-1-\frac{1}{5}\cdot\frac{6}{7}\)
\(=\frac{1}{5}\cdot\left(\frac{1}{7}+\frac{12}{7}-\frac{6}{7}\right)-\left(1-\frac{4}{5}\right)\)
\(=\frac{1}{5}.1-\frac{1}{5}\)
\(=\frac{1}{5}-\frac{1}{5}=0\)
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a) 20,18 x 36 + 63 x 20,18 + 20,18
= 20,18 x ( 36+63+1)
= 20,18 x 100
= 2018
b) \(\frac{a}{b}\times\frac{3}{5}=\frac{1}{5}+\frac{2}{3}\)
\(\frac{a}{b}\times\frac{3}{5}=\frac{13}{15}\)
\(\frac{a}{b}=\frac{13}{15}:\frac{3}{5}\)
\(\frac{a}{b}=\frac{13}{9}\)
a) 20,18.(36+63+1)
= 20,18 . 100
= 2018
a/b . 3/5 =3/15 + 10/15
a/b . 3/5 =13/15
a/b = 13/15 : 3/5
a/b = 13/9
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\(\frac{1}{2}\times\frac{1}{2}+\frac{1}{2}\times\frac{1}{3}+...+\frac{1}{5}\times\frac{1}{6}\)
\(=\frac{1}{4}+\frac{1}{2\times3}+\frac{1}{3\times4}+\frac{1}{4\times5}+\frac{1}{5\times6}\)
\(=\frac{1}{4}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}\)
\(=\frac{1}{4}+\frac{1}{2}-\frac{1}{6}\)
\(=\frac{3+6-2}{12}=\frac{7}{12}\)
\(\frac{1}{2}\)* \(\frac{1}{2}\)+ \(\frac{1}{2}\)*\(\frac{1}{3}\)+ \(\frac{1}{3}\)* \(\frac{1}{4}\)+ \(\frac{1}{4}\)* \(\frac{1}{5}\)+ \(\frac{1}{5}\)* \(\frac{1}{6}\)
=\(\frac{1}{2}\)* \(\frac{1}{6}\)= \(\frac{1}{12}\)
( Những phân số khác nhau bạn loại đi nhé tại mình ko làm được bước đó trên này bạn thông cảm nhé ! )
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\frac{\left(\frac{3}{20}+\frac{1}{2}-\frac{1}{5}\right).\frac{12}{49}}{3\frac{1}{3}+\frac{2}{9}}=\frac{\left(\frac{3}{20}+\frac{1}{2}-\frac{1}{5}\right).\frac{12}{49}}{\frac{10}{3}+\frac{2}{9}}=\frac{\left(\frac{13}{20}-\frac{1}{5}\right).\frac{12}{49}}{\frac{32}{9}}=\frac{\frac{9}{20}.\frac{12}{49}}{\frac{32}{9}}=\frac{\frac{27}{245}}{\frac{32}{9}}=\frac{243}{7840}\)
Có đúng không vu bao quynh?
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a)\(\frac{21}{11}x\frac{22}{17}x\frac{68}{63}\)
=\(\frac{21x22x68}{11x17x63}\)
=\(\frac{21x11x2x17x4}{11x17x21x3}\)
=\(\frac{2x4}{3}\)
=\(\frac{8}{3}\)
b)\(\frac{5}{14}x\frac{7}{13}x\frac{26}{25}\)
=\(\frac{5x7x26}{14x13x25}\)
\(=\frac{2}{3}\)x \(\left(\frac{5}{12}+\frac{7}{12}\right)\)+\(\frac{1}{3}\)
\(=\frac{2}{3}\)x \(1\)+\(\frac{1}{3}\)= \(\frac{2}{3}+\frac{1}{3}\)= \(\frac{3}{3}=1\)
= 2/3 x ( 5/12+7/12 ) +1/3
= 2/3 X 1 +1/3
= 2/3+ 1/3 = 1