\(\dfrac{\dfrac{3}{8}-\dfrac{3}{10}+\dfrac{3}{11}+\dfrac{3}{12}}{-\dfrac{5}{8}+\dfrac{5}{10}-\dfrac{5}{11}-\dfrac{5}{12}}\)
So sánh hai phân số:
a) \(\dfrac{1}{5}\) và \(\dfrac{3}{5}\) b) \(\dfrac{9}{10}\) và \(\dfrac{3}{10}\) c) \(\dfrac{7}{12}\) và \(\dfrac{11}{12}\) d) \(\dfrac{7}{8}\) và \(\dfrac{5}{8}\)
e) \(\dfrac{17}{100}\) và \(\dfrac{23}{100}\) g) \(\dfrac{4}{10}\) và \(\dfrac{1}{10}\) h) \(\dfrac{100}{100}\) và \(\dfrac{49}{100}\) k) \(\dfrac{15}{15}\) và \(\dfrac{2}{15}\)
a) \(< \)
b) \(>\)
c) \(< \)
d) \(>\)
e) \(< \)
g) \(>\)
h) \(>\)
k) \(>\)
Tính:
a) \(\dfrac{-1}{2}+\dfrac{5}{6}+\dfrac{1}{3}\);
b) \(\dfrac{-3}{8}+\dfrac{7}{4}-\dfrac{1}{12}\);
c) \(\dfrac{3}{5}:\left(\dfrac{1}{4}\cdot\dfrac{7}{5}\right)\);
d) \(\dfrac{10}{11}+\dfrac{4}{11}:4-\dfrac{1}{8}\).
a: \(\dfrac{-1}{2}+\dfrac{5}{6}+\dfrac{1}{3}\)
\(=\dfrac{-3}{6}+\dfrac{5}{6}+\dfrac{2}{6}\)
\(=\dfrac{4}{6}=\dfrac{2}{3}\)
b: \(\dfrac{-3}{8}+\dfrac{7}{4}-\dfrac{1}{12}\)
\(=\dfrac{-9}{24}+\dfrac{42}{24}-\dfrac{2}{24}\)
\(=\dfrac{31}{24}\)
c: \(\dfrac{3}{5}:\left(\dfrac{1}{4}\cdot\dfrac{7}{5}\right)=\dfrac{3}{4}:\dfrac{7}{20}=\dfrac{3}{4}\cdot\dfrac{20}{7}=\dfrac{15}{7}\)
d: \(\dfrac{10}{11}+\dfrac{4}{11}:4-\dfrac{1}{8}\)
\(=\dfrac{10}{11}+\dfrac{1}{11}-\dfrac{1}{8}=\dfrac{7}{8}\)
Tính:
a) \(\dfrac{11}{10}+\dfrac{3}{5}:\dfrac{2}{3}\)
b) \(\dfrac{4}{3}\) + 5 x \(\dfrac{5}{8}\)
c) \(\left(\dfrac{2}{5}+\dfrac{3}{7}\right)x\dfrac{25}{29}\)
d) \(\dfrac{1}{4}x\dfrac{5}{12}+\dfrac{5}{12}x\dfrac{4}{5}\)
a) \(\dfrac{11}{10}+\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{11}{10}+\dfrac{3}{5}\times\dfrac{3}{2}=\dfrac{11}{10}+\dfrac{9}{10}=\dfrac{20}{10}=2\)
b) \(\dfrac{4}{3}+5\times\dfrac{5}{8}=\dfrac{4}{3}+\dfrac{25}{8}=\dfrac{32}{24}+\dfrac{75}{24}=\dfrac{107}{24}\)
c) \(\left(\dfrac{2}{5}+\dfrac{3}{7}\right)\times\dfrac{25}{29}=\left(\dfrac{14}{35}+\dfrac{15}{35}\right)\times\dfrac{25}{39}=\dfrac{29}{35}\times\dfrac{25}{39}=\dfrac{145}{274}\)
d) \(\dfrac{1}{4}\times\dfrac{5}{12}+\dfrac{5}{12}\times\dfrac{4}{5}=\dfrac{5}{12}\times\left(\dfrac{1}{4}+\dfrac{4}{5}\right)=\dfrac{5}{12}\times\dfrac{21}{20}=\dfrac{105}{240}=\dfrac{7}{16}\)
a) \(\dfrac{11}{10}+\dfrac{3}{5}x\dfrac{3}{2}=\dfrac{11}{10}+\dfrac{9}{10}=\dfrac{20}{10}=2\)
b) \(\dfrac{4}{3}+\dfrac{25}{8}=\dfrac{32}{24}+\dfrac{75}{24}=\dfrac{107}{24}\)
c) \(\dfrac{29}{35}x\dfrac{25}{29}=\dfrac{5}{7}\)
\(=\dfrac{5}{12}x\left(\dfrac{1}{4}+\dfrac{4}{5}\right)=\dfrac{5}{12}x\dfrac{21}{20}=\dfrac{7}{16}\)
3. Tính :
a/ \(\dfrac{-1}{2}\) + \(\dfrac{5}{6}\) + \(\dfrac{1}{3}\) b/ \(\dfrac{-3}{8}\) + \(\dfrac{7}{4}\) - \(\dfrac{1}{12}\) c/ \(\dfrac{3}{5}\) : (\(\dfrac{1}{4}\) . \(\dfrac{7}{5}\)) d/ \(\dfrac{10}{11}\) + \(\dfrac{4}{11}\) : 4 - \(\dfrac{1}{8}\)
3.a)\(\dfrac{-1}{2}+\dfrac{5}{6}+\dfrac{1}{3}=\dfrac{-3}{6}+\dfrac{5}{6}+\dfrac{2}{6}=\dfrac{-3+5+2}{6}=\dfrac{4}{6}=\dfrac{2}{3}\)
b)\(\dfrac{-3}{8}+\dfrac{7}{4}-\dfrac{1}{12}=\dfrac{-9}{24}+\dfrac{42}{24}-\dfrac{2}{24}=\dfrac{-9+42-2}{24}=\dfrac{31}{24}\)
c)\(\dfrac{3}{5}:\left(\dfrac{1}{4}.\dfrac{7}{5}\right)=\dfrac{3}{5}:\dfrac{7}{20}=\dfrac{3}{5}.\dfrac{20}{7}=\dfrac{12}{7}\)
d)\(\dfrac{10}{11}+\dfrac{4}{11}:4-\dfrac{1}{8}=\dfrac{10}{11}+\dfrac{4}{11}.\dfrac{1}{4}-\dfrac{1}{8}=\dfrac{10}{11}+\dfrac{1}{11}-\dfrac{1}{8}=1-\dfrac{1}{8}=\dfrac{8}{8}-\dfrac{1}{8}=\dfrac{7}{8}\)
Bài1 tính:
a)\(\dfrac{2}{5}\)+\(\dfrac{5}{12}\); b)\(\dfrac{2}{3}\) - \(\dfrac{3}{8}\); c)\(\dfrac{3}{7}\) ✖ \(\dfrac{4}{9}\); d) \(\dfrac{11}{10}\) - \(\dfrac{2}{5}\) ː \(\dfrac{2}{3}\)
2/5+5/12
=49/60
2/3-3/8
=7/24
3/7.4/9
=4/21
11/10-2/5:2/3
=11/10-3/5
=1/2
\(\dfrac{1}{8}-\dfrac{1}{2}+(\dfrac{-11}{12}+1)\)
\(\dfrac{3}{5}-\dfrac{-7}{10}+\dfrac{-13}{10}\)
`1/8 -1/2 + (-11/12 + 1)`
`=1/8 -1/2 + (-11/12 +12/12)`
`=1/8 -1/2 + 1/12`
`= 1/8- 4/8+1/12`
`= -3/8 + 1/12`
`=-7/24`
`---------`
`3/5 -(-7/10) + (-13/10)`
`= 3/5 + 7/10 + (-13/10)`
`= 6/10 + 7/10 + (-13/10)`
`= 13/10 +(-13/10)`
`= 0/10=0`
\(\dfrac{1}{8}-\dfrac{1}{2}+\left(\dfrac{-11}{12}+1\right)\\ =\dfrac{-3}{8}+\dfrac{1}{12}\\ =\dfrac{-7}{24}\\ \dfrac{3}{5}-\dfrac{-7}{10}+\left(-\dfrac{13}{10}\right)\\ =\dfrac{13}{10}-\dfrac{13}{10}\\ =0\)
\(\dfrac{1}{8}-\dfrac{1}{2}+\left(\dfrac{-11}{12}+1\right)=\dfrac{-3}{8}+\dfrac{1}{12}=\dfrac{-7}{24}\)
\(\dfrac{3}{5}-\dfrac{-7}{10}+\dfrac{-13}{10}=\dfrac{6}{10}-\dfrac{-7}{10}+\dfrac{-13}{10}=\dfrac{13}{10}+\dfrac{-13}{10}=\dfrac{0}{10}=0\)
Tính một cách hợp lí:
a) \(\dfrac{2}{9}+\dfrac{-3}{10}+\dfrac{-7}{10}\);
b) \(\dfrac{-11}{6}+\dfrac{2}{5}+\dfrac{-1}{6};\)
c) \(\dfrac{-5}{8}+\dfrac{12}{7}+\dfrac{13}{8}+\dfrac{2}{7}.\)
\(a.\)
\(\dfrac{2}{9}+\dfrac{-3}{10}+-\dfrac{7}{10}=\dfrac{2}{9}-1=\dfrac{2}{9}-\dfrac{9}{9}=-\dfrac{7}{9}\)
\(b.\)
\(\dfrac{-11}{6}+\dfrac{2}{5}+\dfrac{-1}{6}=\left(-\dfrac{11}{6}+-\dfrac{1}{6}\right)+\dfrac{2}{5}=-2+\dfrac{2}{5}=\dfrac{-10}{5}+\dfrac{2}{5}=\dfrac{-8}{5}\)
\(c.\)
\(-\dfrac{5}{8}+\dfrac{12}{7}+\dfrac{13}{8}+\dfrac{2}{7}=\left(-\dfrac{5}{8}+\dfrac{13}{8}\right)+\left(\dfrac{12}{7}+\dfrac{2}{7}\right)=1+2=3\)
Tính hợp lí:
g) \(\dfrac{-3}{4}+\dfrac{2}{7}+\dfrac{-1}{4}+\dfrac{3}{5}+\dfrac{5}{7}\)
h) \(\dfrac{7}{19}.\dfrac{8}{11}+\dfrac{7}{19}.\dfrac{3}{11}-\dfrac{12}{19}\)
i) \(19\dfrac{5}{8}:\dfrac{7}{2013}-26\dfrac{5}{8}:\dfrac{7}{2013}\)
k) \(\dfrac{-5}{12}.\dfrac{2}{11}+\dfrac{-5}{12}.\dfrac{9}{11}+\dfrac{5}{12}\)
g: \(=\dfrac{-3}{4}-\dfrac{1}{4}+\dfrac{5}{7}+\dfrac{2}{7}+\dfrac{3}{5}=\dfrac{3}{5}\)
h: \(=\dfrac{7}{19}\left(\dfrac{8}{11}+\dfrac{3}{11}\right)-\dfrac{12}{19}=\dfrac{7}{19}-\dfrac{12}{19}=-\dfrac{5}{19}\)
i: \(=\dfrac{2013}{7}\left(19+\dfrac{5}{8}-26-\dfrac{5}{8}\right)=\dfrac{2013}{7}\cdot\left(-7\right)=-2013\)
Bài 1: Thực hiện phép tính:
a, \(\left(\dfrac{7}{20}+\dfrac{11}{15}-\dfrac{15}{12}\right):\left(\dfrac{11}{20}-\dfrac{26}{45}\right)\)
b, \(\dfrac{5-\dfrac{5}{3}+\dfrac{5}{9}-\dfrac{5}{27}}{8-\dfrac{8}{3}+\dfrac{8}{9}-\dfrac{8}{27}}:\dfrac{15-\dfrac{15}{11}+\dfrac{15}{121}}{16-\dfrac{16}{11}+\dfrac{16}{121}}\)
c, \(\dfrac{\dfrac{1}{9}-\dfrac{5}{6}-4}{\dfrac{7}{12}-\dfrac{1}{36}-10}\)
\(a,\left(\dfrac{7}{20}+\dfrac{11}{15}-\dfrac{15}{12}\right):\left(\dfrac{11}{20}-\dfrac{26}{45}\right).\)
\(=\left(\dfrac{21}{60}+\dfrac{44}{60}-\dfrac{75}{60}\right):\left(\dfrac{99}{180}-\dfrac{104}{180}\right).\)
\(=\left(\dfrac{65}{60}-\dfrac{75}{60}\right):\left(-\dfrac{5}{180}\right).\)
\(=-\dfrac{10}{60}:\left(-\dfrac{5}{180}\right).\)
\(=-\dfrac{1}{6}:\left(-\dfrac{1}{36}\right).\)
\(=-\dfrac{1}{6}.\left(-36\right).\)
\(=\dfrac{-1.\left(-36\right)}{6}=\dfrac{36}{6}=6.\)
Vậy......
\(b,\dfrac{5-\dfrac{5}{3}+\dfrac{5}{9}-\dfrac{5}{27}}{8-\dfrac{8}{3}+\dfrac{8}{9}-\dfrac{8}{27}}:\dfrac{15-\dfrac{15}{11}+\dfrac{15}{121}}{16-\dfrac{16}{11}+\dfrac{16}{121}}.\)
\(=\dfrac{5\left(1-\dfrac{1}{3}+\dfrac{1}{9}-\dfrac{1}{27}\right)}{8\left(1-\dfrac{1}{3}+\dfrac{1}{9}-\dfrac{1}{27}\right)}:\dfrac{15\left(1-\dfrac{1}{11}+\dfrac{1}{121}\right)}{16\left(1-\dfrac{1}{11}+\dfrac{1}{121}\right)}.\)
\(=\dfrac{5}{8}:\dfrac{15}{16}.\)
\(=\dfrac{5}{8}.\dfrac{16}{15}=\dfrac{5.16}{8.15}=\dfrac{1.2}{1.3}=\dfrac{2}{3}.\)
Vậy......
c, (làm tương tự câu b).
~ Học tốt!!! ~