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\(\dfrac{2}{5}< \dfrac{3}{7}\)
\(\dfrac{2}{7}< \dfrac{4}{9}\)
\(\dfrac{5}{8}< \dfrac{8}{5}\)
\(\dfrac{11}{18}< \dfrac{5}{6}\)
\(\dfrac{7}{8}< \dfrac{11}{12}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
c) \(\dfrac{6}{7}-\dfrac{3}{4}=\dfrac{3}{28}\)
d) \(\dfrac{35}{28}-\dfrac{48}{64}=\dfrac{1}{2}\)
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a: \(=\left(\dfrac{21}{11}+\dfrac{12}{11}\right)+\left(-\dfrac{9}{19}-\dfrac{3}{19}-\dfrac{6}{19}\right)=3-\dfrac{18}{19}=\dfrac{57}{19}-\dfrac{18}{19}=\dfrac{39}{19}\)
b: \(=\left(\dfrac{2}{3}+\dfrac{4}{3}\right)+\left(\dfrac{3}{4}+\dfrac{7}{4}\right)+\left(\dfrac{4}{5}+\dfrac{16}{5}\right)=2+4+\dfrac{5}{2}=6+\dfrac{5}{2}=\dfrac{17}{2}\)
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\(\frac{232}{16}-\frac{658}{456}\)
\(=\frac{19}{2}-\frac{329}{228}\)
\(=\frac{2166}{228}-\frac{329}{228}\)
\(=\frac{2166-329}{228}\)
\(=\frac{1837}{228}\)
Vậy 232/16 - 658/456 = 1837/228
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a,\(\dfrac{2}{5}+\dfrac{1}{10}=\dfrac{4}{10}+\dfrac{1}{10}=\dfrac{5}{10}=\dfrac{1}{2}\)
\(b,3-\dfrac{1}{2}=\dfrac{3}{1}-\dfrac{1}{2}=\dfrac{6}{2}-\dfrac{1}{2}=\dfrac{5}{2}\)
\(c,\dfrac{7}{12}x\dfrac{12}{21}=\dfrac{1}{3}\)
\(d,4:\dfrac{2}{3}=\dfrac{4}{1}:\dfrac{2}{3}=\dfrac{4}{1}x\dfrac{3}{2}=\dfrac{6}{1}=6\)
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Bài 1: Cạnh hình vuông giảm 3 lần thì diện tích giảm 9 lần
Bài 2: Chiều dài HCN tăng 4 lần, chiều rộng giảm đi một nửa thì diện tích HCN tăng 2 lần
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Đoàn xe thứ nhất chở:
98 : 7 x 3 = 42 (tấn gạo)
Đoàn xe thứ 2 chở :
98 - 42 = 56 (tấn gạo)
\(a,\dfrac{2}{7}+\dfrac{1}{4}=\dfrac{8}{28}+\dfrac{7}{28}=\dfrac{15}{28}\\ b,\dfrac{3}{5}+\dfrac{3}{8}=\dfrac{3.8}{5.8}+\dfrac{3.5}{5.8}=\dfrac{6}{5}\\ c,=\dfrac{4.3}{9.3}+\dfrac{10}{27}=\dfrac{12+10}{27}=\dfrac{22}{27}\\ d,=\dfrac{2.3}{3.3}+\dfrac{7}{9}=\dfrac{6+7}{9}=\dfrac{13}{9}\\ e,=\dfrac{5.5}{12.5}+\dfrac{7.4}{15.4}=\dfrac{25+28}{60}=\dfrac{53}{60}\)
\(\dfrac{2}{7}+\dfrac{1}{4}=\dfrac{8}{28}+\dfrac{7}{28}=\dfrac{15}{28};\dfrac{3}{5}+\dfrac{3}{8}=\dfrac{24}{40}+\dfrac{15}{40};\dfrac{4}{9}+\dfrac{10}{27}=\dfrac{12}{27}+\dfrac{10}{27}=\dfrac{22}{27};\dfrac{2}{3}+\dfrac{7}{9}=\dfrac{18}{27}+\dfrac{21}{27}=\dfrac{39}{27};\dfrac{5}{12}+\dfrac{7}{15}=\dfrac{75}{180}+\dfrac{84}{180}=\dfrac{159}{180}\)