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bài làm
a) \(\frac{5}{8}-\frac{2}{5}\)
\(=\frac{25}{40}-\frac{16}{40}\)
\(=\frac{9}{40}\)
b) \(1\frac{1}{10}-\frac{3}{4}\)
\(=\frac{11}{10}-\frac{3}{4}\)
\(=\frac{22}{20}-\frac{15}{20}\)
\(=\)\(\frac{7}{20}\)
c) \(\frac{2}{3}+\frac{1}{2}-\frac{5}{6}\)
\(=\frac{4}{6}+\frac{3}{6}-\frac{5}{6}\)
\(=\frac{4+3-5}{6}\)
\(=\frac{2}{6}\)
\(=\frac{1}{3}\)
chúc bạn học tốt
\(\frac{2}{3}.\frac{4}{5}+\frac{1}{3}.\frac{4}{5}=\frac{4}{5}\left(\frac{2}{3}+\frac{1}{3}\right)=\frac{4}{5}.\frac{3}{3}=\frac{4}{5}.1=\frac{4}{5}\)
\(\frac{1}{2}:\frac{3}{4}+\frac{1}{6}:\frac{3}{4}=\frac{3}{4}:\left(\frac{1}{2}+\frac{1}{6}\right)=\frac{3}{4}:\frac{2}{3}=\frac{9}{8}\)
\(\frac{2}{3}.\frac{4}{5}-\frac{1}{3}.\frac{4}{5}=\frac{4}{5}\left(\frac{2}{3}-\frac{1}{3}\right)=\frac{4}{5}.\frac{1}{3}=\frac{4}{15}\)
\(\frac{1}{2}:\frac{3}{4}-\frac{1}{6}:\frac{3}{4}=\frac{3}{4}:\left(\frac{1}{2}-\frac{1}{6}\right)=\frac{3}{4}:\frac{1}{3}=\frac{9}{4}\)
\(\frac{2}{3}.\frac{4}{5}+\frac{1}{3}.\frac{4}{5}=\left(\frac{2}{3}+\frac{1}{3}\right).\frac{4}{5}=1.\frac{4}{5}=\frac{4}{5}\)
\(\frac{1}{2}:\frac{3}{4}+\frac{1}{6}:\frac{3}{4}=\frac{1}{2}.\frac{4}{3}+\frac{1}{6}.\frac{4}{3}=\left(\frac{1}{2}+\frac{1}{6}\right).\frac{4}{3}=\frac{2}{3}.\frac{4}{3}=\frac{8}{9}\)
c,d tương tự
ta có 5/7 = 30/42; 5/6= 35/42
5 phân số bé hơn 5/7 và 5/6 là
31/42;32/42;33/42;34/42;35/42.
12/7:x+2/3=7/5
=> 12/7:x = 7/5-2/3
=> 12/7 :x = 11/15
=> x = 12/7 : 11/5
=> x = 180/77
bn k giúp mik nha
\(\frac{\frac{5}{7}+\frac{6}{11}+\frac{7}{13}}{\frac{10}{7}+\frac{12}{11}+\frac{14}{13}}\)
\(=\frac{\frac{5}{7}+\frac{6}{11}+\frac{7}{13}}{2\left(\frac{5}{7}+\frac{6}{11}+\frac{7}{13}\right)}\)
\(=\frac{1}{2}\)
\(3\frac{4}{5}:\frac{3}{7}+3\frac{4}{5}:\frac{3}{26}-\frac{19}{5}\)
= \(3\frac{4}{5}.\frac{7}{3}+3\frac{4}{5}.\frac{26}{3}-\frac{19}{5}\)
= \(3\frac{4}{5}.\left(\frac{7}{3}+\frac{26}{3}\right)-\frac{19}{5}\)
= \(3\frac{4}{5}.11-\frac{19}{5}\)
= \(41\frac{4}{5}-\frac{19}{5}\)
= \(38\)
~~~
#Sunrise
3/4/5:3/7+3/4/5:3/26-19/5
=3/4/5+(3/7+3/26)-19/5
=3/4/5+99/182-19/5
=(3/4/5-19/5)+99/182
=0+99/182
=99/182
a/
\(1\frac{1}{2}x1\frac{1}{3}x1\frac{1}{4}x1\frac{1}{5}x1\frac{1}{6}=\frac{3}{2}x\frac{4}{3}x\frac{5}{4}x\frac{6}{5}x\frac{7}{6}=\frac{7}{2}=3\frac{1}{2}\)
b/
x=0; y=5
\(\left(1-\frac{1}{2}\right)\cdot\left(1-\frac{1}{3}\right)\cdot\left(1-\frac{1}{4}\right)\cdot...\cdot\left(1-\frac{1}{7}\right)\)
\(=\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{3}{4}\cdot\frac{4}{5}\cdot\frac{5}{6}\cdot\frac{6}{7}\)
\(=\frac{\left(1\cdot2\cdot3\cdot4\cdot5\cdot6\right)}{\left(2\cdot3\cdot4\cdot5\cdot6\cdot7\right)}\)
\(=\frac{1}{7}\)
C1 : \(\frac{7}{11}\):\(\frac{3}{5}\)+\(\frac{4}{11}\):\(\frac{3}{5}\)
=\(\frac{7}{11}\)x\(\frac{5}{3}\)+\(\frac{4}{11}\)x\(\frac{5}{3}\)
=\(\frac{35}{33}\)+\(\frac{20}{33}\)
=\(\frac{55}{33}\)=\(\frac{5}{3}\)
C2: \(\frac{7}{11}\):\(\frac{3}{5}\)+\(\frac{4}{11}\):\(\frac{3}{5}\)
= \(\frac{3}{5}\)x (\(\frac{7}{11}\)+\(\frac{4}{11}\))
=\(\frac{3}{5}\)x 1= \(\frac{3}{5}\)
\(C1:\frac{7}{11}:\frac{3}{5}+\frac{4}{11}:\frac{3}{5}\)
\(=\frac{7}{11}x\frac{5}{3}+\frac{4}{11}x\frac{5}{3}\)
\(=\frac{35}{33}+\frac{20}{33}\)
\(=\frac{55}{33}=\frac{5}{3}\)
\(C2:\frac{7}{11}:\frac{3}{5}+\frac{4}{11}:\frac{3}{5}\)
\(=\frac{7}{11}x\frac{5}{3}+\frac{4}{11}x\frac{5}{3}\)
\(=\frac{5}{3}x\left(\frac{7}{11}+\frac{4}{11}\right)\)
\(=\frac{5}{3}x1=\frac{5}{3}\)
BÀi này cậu vận dụng kiến thức về phân số ở Tiểu học
tk mình nhé
Nếu giải ra thì tốn sức lắm
(4/5:6/5:1/y)x30-26=54
=> ( 2/3.y)x30 = 54+26
=> ( 2/3.y)x30=80
=> 2/3.y=80:30
=>2/3.y=8/3
=> y=8/3:2/3
=> y=4
vậy y =4
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