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`a,3/10=0,3`
`3/100=0,03`
`4 25/100=4 1/4=4,25`
`2002/1000=2,002`
`b,1/4=0,25`
`3/5=0,6`
`7/8=0,875`
`1 1/2=1,5`
`3/7-2/5`
`=1/35>0`
`=>3/7>2/5`
`b,9>8`
`=>1/9<1/8`
`=>5/9<5/8`
`d,8/7>1`
`7/8<1`
`=>8/7>7/8`
\(\dfrac{3}{5}m=0,6m\)
\(\dfrac{7}{20}m=0,35m\)
\(\dfrac{5}{4}m=1,25m\)
a, \(\dfrac{3}{4}\) = \(\dfrac{3\times5}{4\times5}\) = \(\dfrac{15}{20}\) \(\dfrac{5}{7}\) = \(\dfrac{5\times3}{7\times3}\) = \(\dfrac{15}{21}\)
Vì \(\dfrac{15}{20}\) > \(\dfrac{15}{21}\) nên \(\dfrac{3}{4}\) > \(\dfrac{5}{7}\)
b, \(\dfrac{2}{7}\) = \(\dfrac{2\times2}{7\times2}\) = \(\dfrac{4}{14}\) < \(\dfrac{4}{9}\)
Vậy \(\dfrac{2}{7}\) < \(\dfrac{4}{9}\)
c, \(\dfrac{5}{8}\) < 1 < \(\dfrac{8}{5}\)
Vậy \(\dfrac{5}{8}\) < \(\dfrac{8}{5}\)
a, \(\dfrac{7}{8}\) \(\times\) \(\dfrac{3}{13}\) + \(\dfrac{4}{9}\) \(\times\) \(\dfrac{4}{13}\)
= \(\dfrac{1}{13}\) \(\times\)( \(\dfrac{21}{8}\) + \(\dfrac{16}{9}\))
= \(\dfrac{1}{13}\) \(\times\)( \(\dfrac{189}{72}\) + \(\dfrac{128}{72}\))
= \(\dfrac{1}{13}\) \(\times\) \(\dfrac{317}{73}\)
= \(\dfrac{317}{949}\)
b, \(\dfrac{6}{5}\) + \(\dfrac{7}{3}\) + \(\dfrac{8}{9}\)
= \(\dfrac{54}{45}\) + \(\dfrac{105}{45}\) + \(\dfrac{40}{45}\)
= \(\dfrac{199}{45}\)
c, 23 : \(\dfrac{5}{14}\) + \(\dfrac{6}{7}\) + \(\dfrac{4}{9}\)
= \(\dfrac{322}{5}\) + \(\dfrac{6}{7}\) + \(\dfrac{4}{9}\)
= \(\dfrac{20286}{315}\) + \(\dfrac{270}{315}\) + \(\dfrac{140}{315}\)
= \(\dfrac{20696}{315}\)
d, 4\(\dfrac{1}{4}\) + 7\(\dfrac{3}{7}\) - 2\(\dfrac{4}{17}\)
= 4 + \(\dfrac{1}{4}\) + 7 + \(\dfrac{3}{7}\) - 2 - \(\dfrac{4}{17}\)
= (4+7-2) + (\(\dfrac{1}{4}\) + \(\dfrac{3}{7}\) - \(\dfrac{4}{17}\))
= 9 + \(\dfrac{119}{476}\) + \(\dfrac{204}{476}\) - \(\dfrac{112}{476}\)
= 9\(\dfrac{211}{476}\) = \(\dfrac{4495}{476}\)
e, 8 - (9\(\dfrac{2}{11}\) + \(\dfrac{8}{33}\))
= 8 - 9 - \(\dfrac{2}{11}\) - \(\dfrac{8}{33}\)
= -1 - \(\dfrac{2}{11}\) - \(\dfrac{8}{33}\)
= \(\dfrac{-33}{33}\) - \(\dfrac{-6}{33}\) - \(\dfrac{8}{33}\)
= - \(\dfrac{47}{33}\)
`@` `\text {Ans}`
`\downarrow`
`1,`
Ta có: `12 > 9 > 8 > 7`
`=> 12/8 > 9/8 > 8/8 > 7/8`
`=>` Phân số lớn nhất là `12/8`
`=> A.`
`2,`
So sánh \(\dfrac{3}{4}\text{ ; }\dfrac{9}{32}\)
\(\dfrac{3}{4}=\dfrac{3\times8}{4\times8}=\dfrac{24}{32}\)
Vì `24 > 9 `\(\Rightarrow\dfrac{24}{32}>\dfrac{9}{32}\) \(\Rightarrow\dfrac{3}{4}>\dfrac{9}{32}\)
\(\dfrac{9}{32}\text{;}\dfrac{3}{11}\)
\(\dfrac{9}{32}=\dfrac{9\times11}{32\times11}=\dfrac{99}{352}\)
\(\dfrac{3}{11}=\dfrac{3\times32}{11\times32}=\dfrac{96}{352}\)
Vì `99 > 96 \Rightarrow`\(\dfrac{99}{352}>\dfrac{96}{352}\Rightarrow\dfrac{9}{32}>\dfrac{3}{11}\)
Mà \(\dfrac{3}{11}< \dfrac{3}{4}\); \(\dfrac{9}{32}< \dfrac{3}{4}\)
`\Rightarrow`\(\dfrac{3}{4}>\dfrac{9}{32}>\dfrac{3}{11}\)
So sánh \(\dfrac{5}{7};\dfrac{3}{4}\)
\(\dfrac{5}{7}=\dfrac{5\times4}{7\times4}=\dfrac{20}{28}\)
\(\dfrac{3}{4}=\dfrac{3\times7}{4\times7}=\dfrac{21}{28}\)
Vì \(20< 21\Rightarrow\dfrac{20}{28}< \dfrac{21}{28}\Rightarrow\dfrac{5}{7}< \dfrac{3}{4}\)
So sánh \(\dfrac{5}{7};\dfrac{9}{32}\)
\(\dfrac{5}{7}=\dfrac{5\times32}{7\times32}=\dfrac{160}{224}\)
\(\dfrac{9}{32}=\dfrac{9\times7}{32\times7}=\dfrac{64}{224}\)
Vì \(160>64\Rightarrow\dfrac{160}{224}>\dfrac{64}{224}\Rightarrow\dfrac{5}{7}>\dfrac{9}{32}\)
`\Rightarrow` Thứ tự sắp xếp các phân số tăng dần là: \(\dfrac{3}{11};\dfrac{9}{32};\dfrac{5}{7};\dfrac{3}{4}\)
Bài 1 : A 12/8
Bài 2 : Theo thứ tự tăng dần là : 3/11, 9/32, 5/7, 3/4
B
B