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9 tháng 2 2019
\(3+\frac{2}{5}-\frac{3}{4}\times\frac{4}{5}\)
\(=3+\frac{2}{5}-\frac{3}{4}\)
\(=\frac{3\times20+2\times4-3\times5}{20}\)
\(=\frac{60+8-15}{20}\)
\(=\frac{68-15}{20}\)
\(=\frac{53}{20}\)
9 tháng 2 2019
\(5-\frac{7}{9}+\frac{2}{3}-\frac{5}{6}:\frac{4}{9}\)
\(=5-\frac{7}{9}+\frac{2}{3}-\frac{45}{24}\)
\(=\frac{5\times72-7\times8+2\times24-45\times3}{72}\)
\(=\frac{360-56+48-135}{72}\)
\(=\frac{217}{72}\)
22 tháng 2 2017
12/5 -4/5 =8/5
11/6 -2/3 =21/18 =7/6
7/8 -2/7 =33/56
4 -8/5 =20/5-8/5 =12/5
2 -3/8 =16/8 -3/8 =13/8
16/7 -2 =16/7 -14/7 =2/7
25/4 -3=25/4 -12/4 =13/4
NV
22 tháng 2 2017
câu 2 : câu 3 :
a) 8/5 a)4 - 8/5 = 20/5 - 8/5 =12/5
b) 7/6 b)2 - 3/8 =16/8 - 3/8 = 13/8
c) 35/56 c)16/7 - 2 = 16/7 - 14/7 = 2/7
d)25/4 - 3 = 25/4 - 12/4 = 13/4
27 tháng 4 2019
\(\frac{3}{4}+\frac{2}{3}=\frac{9}{12}+\frac{8}{12}=\frac{17}{12}\)
\(\frac{9}{2}-4=\frac{9}{2}-\frac{8}{2}=\frac{1}{2}\)
\(\frac{4}{5}\times\frac{3}{2}=\frac{4\times3}{5\times2}=\frac{12}{10}=\frac{6}{5}\)
\(\frac{5}{6}:\frac{6}{5}=\frac{5}{6}\times\frac{5}{6}=\frac{25}{36}\)
4 tháng 7 2017
bài 1:
\(\frac{6}{11}+\frac{1}{3}+\frac{5}{11}\)
\(=\left(\frac{6}{11}+\frac{5}{11}\right)+\frac{1}{3}\)
\(=\frac{11}{11}+\frac{1}{3}=1+\frac{1}{3}=\frac{3}{3}+\frac{1}{3}=\frac{4}{3}\)
bài 2:
\(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}\)
\(=\left(\frac{1}{2}+\frac{1}{20}\right)+\left(\frac{1}{6}+\frac{1}{12}\right)\)
\(=\frac{11}{20}+\frac{1}{4}=\frac{11}{20}+\frac{5}{20}=\frac{15}{20}=\frac{3}{4}\)
bài 3:
a) \(\frac{3}{2}\cdot\frac{4}{5}\cdot\frac{2}{3}=\left(\frac{3}{2}\cdot\frac{2}{3}\right)\cdot\frac{4}{5}=1\cdot\frac{4}{5}=\frac{4}{5}\)
b) \(\frac{6}{7}\cdot\frac{5}{3}\cdot\frac{7}{6}=\left(\frac{6}{7}\cdot\frac{7}{6}\right)\cdot\frac{5}{3}=1\cdot\frac{5}{3}=\frac{5}{3}\)
bài 4:
a) \(\frac{2}{5}\cdot\frac{1}{4}+\frac{3}{4}\cdot\frac{2}{5}=\frac{2}{5}\cdot\left(\frac{1}{4}+\frac{3}{4}\right)=\frac{2}{5}\cdot1=\frac{2}{5}\)
b) \(\frac{6}{11}:\frac{2}{3}+\frac{5}{11}:\frac{2}{3}=\left(\frac{6}{11}+\frac{5}{11}\right):\frac{2}{3}=1:\frac{2}{3}=\frac{3}{2}\)
4 tháng 7 2017
Bài 1:
6/11 + 1/3 + 5/11
= ( 6/11 + 5/11) + 1/3
= 11/11 + 1/3
= 1 + 1/3
= 3/3 +1/3
= 4/3
Bài 2:
1/2 + 1/6 + 1/12 + 1/20
= ( 1/2 + 1/6 + 1/12 ) + 1/20
= ( 6/12 + 2/12 + 1/12 ) + 1/20
=9/12 + 1/20
= 3/4 +1/20
= 15/20 + 1/20
= 16/20 = 4/5
Bài 3:
a) \(\frac{3}{2}\times\frac{4}{5}\times\frac{2}{3}\) \(=\left(\frac{3}{2}\times\frac{2}{3}\right)\times\frac{4}{5}\)\(=1\times\frac{4}{5}=\frac{4}{5}\)
b) \(\frac{6}{7}\times\left(\frac{5}{3}\times\frac{7}{6}\right)\) \(=\frac{6}{7}\times\frac{35}{18}\)\(=\frac{1\times5}{7\times3}=\frac{5}{21}\)
Bài 4:
a) 2/5 x 1/4 + 3/4 x 2/5
= 2/5 x ( 1/4 + 3/4)
= 2/5 x 1
= 2/5
b) 6/11 : 2/3 +5/11 : 2/3
= ( 6/11 + 5/11) x 3/2
= 11/11 x 3/2
= 1 x 3/2
= 3/2
....
28 tháng 8 2019
\(\frac{3}{5}+\frac{2}{7}=\frac{21}{35}+\frac{10}{35}=\frac{31}{35}\)
\(\frac{3}{9}-\frac{1}{5}=\frac{15}{45}-\frac{9}{45}=\frac{6}{45}\)
\(\frac{2}{5}\times\frac{3}{7}=\frac{6}{35}\)
\(\frac{4}{9}:\frac{2}{5}=\frac{4}{9}\times\frac{5}{2}=\frac{20}{18}\)
28 tháng 8 2019
Trả lời
\(\frac{3}{5}+\frac{2}{7}=\frac{21}{35}+\frac{10}{35}=\frac{31}{35}\)
\(\frac{3}{9}-\frac{1}{5}=\frac{15}{45}-\frac{9}{45}=\frac{6}{45}=\frac{2}{15}\)
\(\frac{2}{5}\times\frac{3}{7}=\frac{6}{35}\)
\(\frac{4}{9}:\frac{2}{5}=\frac{4}{9}\times\frac{5}{2}=\frac{20}{18}=\frac{10}{9}\)
Study well
7 tháng 7 2018
a) \(\frac{3}{5}\times y+\frac{1}{2}:\frac{5}{3}-\frac{5}{4}=\frac{1}{2}\times\frac{1}{3}\)
\(\Rightarrow\frac{3}{5}\times y+\frac{3}{10}-\frac{5}{4}=\frac{1}{6}\)
\(\Rightarrow\frac{3}{5}\times y+\left(-\frac{19}{20}\right)=\frac{1}{6}\)
\(\Rightarrow\frac{3}{5}\times y=\frac{67}{60}\)
\(\Rightarrow y=\frac{67}{36}\)
b) \(\frac{4}{5}:y+\frac{1}{4}\times\frac{1}{6}-\frac{1}{2}=\frac{1}{3}\times\frac{5}{2}\)
\(\Rightarrow\frac{4}{5}:y+\frac{1}{24}-\frac{1}{2}=\frac{5}{6}\)
\(\Rightarrow\frac{4}{5}:y+\left(-\frac{11}{24}\right)=\frac{5}{6}\)
\(\Rightarrow\frac{4}{5}:y=\frac{5}{6}+\frac{11}{24}=\frac{31}{24}\)
\(\Rightarrow y=\frac{4}{5}:\frac{31}{24}=\frac{96}{155}\)
c) \(\frac{3}{5}\times y-\frac{4}{5}:3+\frac{1}{12}=\frac{3}{2}+\frac{1}{5}\)
\(\Rightarrow\frac{3}{5}\times y-\frac{4}{15}+\frac{1}{12}=\frac{17}{10}\)
\(\Rightarrow\frac{3}{5}\times y-\frac{4}{15}=\frac{97}{60}\)
\(\Rightarrow\frac{3}{5}\times y=\frac{113}{60}\)
\(\Rightarrow y=\frac{113}{36}\)
3 tháng 3 2019
\(\frac{17}{2}\times\frac{3}{5}+\frac{3}{5}\times\frac{1}{2}+\frac{3}{5}\)
\(=\frac{3}{5}\times\left(\frac{17}{2}+\frac{1}{2}\right)\)
\(=\frac{3}{5}\times9\)
\(=\frac{27}{5}\)
Ai Fan anh Kha diem danh
3 tháng 3 2019
\(\frac{17}{2}\times\frac{3}{5}+\frac{3}{5}\times\frac{1}{2}+\frac{3}{5}\)
\(=\frac{3}{5}\times\left(\frac{17}{2}+\frac{1}{2}+1\right)\)
\(=\frac{3}{5}\times\left(\frac{17}{2}+\frac{1}{2}+\frac{2}{2}\right)\)
\(=\frac{3}{5}\times\frac{20}{2}\)
\(=\frac{60}{10}=6\)
CHÚC BẠN HOK TOT
S
7 tháng 11 2016
a) \(3\frac{4}{7}\times2\frac{4}{5}\)
\(=\frac{25}{7}\times\frac{14}{5}=\frac{350}{35}=10\)
b) \(\frac{4}{5}:\frac{1}{2}+\frac{17}{3}\)
\(=\frac{8}{5}+\frac{17}{3}\)
\(=\frac{109}{15}\)
c) \(5\frac{1}{3}-2\frac{1}{6}\)
\(=\frac{16}{3}-\frac{13}{6}\)
\(=\frac{32}{6}-\frac{13}{6}=\frac{19}{6}\)
d) \(4\frac{1}{2}:2\frac{1}{4}\)
\(=\frac{9}{2}:\frac{9}{4}=\frac{45}{18}\)
6/5 = 1,2
\(\dfrac{3}{5}:2=\dfrac{3}{5}\times\dfrac{1}{2}=\dfrac{3}{10}\)