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28 tháng 6 2021

Ý đầu tiên tớ thấy sai sai ạ:((

\(\frac{4}{3}-\frac{1}{3}.\frac{5}{2}=\frac{4}{3}-\frac{5}{6}=\frac{8-5}{6}=\frac{1}{2}\)

\(\left(\frac{3}{2}-\frac{3}{8}\right):\frac{1}{2}=\left(\frac{12-3}{8}\right):\frac{1}{2}=\frac{9}{4}\)

\(15:\frac{3}{8}.\frac{3}{4}=40.\frac{3}{4}=30\)

Giải:

A=5/9+2/15-6/9

   =(5/9-6/9)+2/15

   = -1/9 + 2/15

   = 1/45

B=2/7-3/8+4/7+1/7-5/8+5/15

   = (2/7+4/7+1/7) + (-3/8-5/8) +1/3

   = 1+ (-1) +1/3

   =1/3

C=3/5+1/15+1/57+1/3-2/9-3/4-1/36

   =9/15+1/15+1/57+19/57-8/36-27/36-1/36

   =(9/15+1/15)+(1/57+19/57)+(-8/36-27/36-1/36)

   =2/3+20/57+(-1)

   =58/57+(-1)

   =1/57

D=1/1.2+1/2.3+1/3.4+...+1/99.100

   =1/1-1/2+1/2-1/3+1/3-1/4+...+1/99-1/100

   =1/1-1/100

   =99/100

Câu E mình ko biết làm nhé!

8 tháng 5 2022

a)\(=\dfrac{3}{3}+\dfrac{4}{3}=\dfrac{7}{3}\)

b)\(=\dfrac{5}{9}\times\dfrac{3}{2}=\dfrac{15}{18}=\dfrac{5}{6}\)

d)\(=\left(\dfrac{12}{8}-\dfrac{3}{8}\right)\times2=\dfrac{9}{8}\times2=\dfrac{18}{8}=\dfrac{9}{4}\)

c)\(=\dfrac{4}{3}-\dfrac{5}{6}=\dfrac{8}{6}-\dfrac{5}{6}=\dfrac{3}{6}=\dfrac{1}{2}\)

8 tháng 5 2022

a) 1 + 4/3 = 7/3

b) 5/9 : 2/3 = 5/6

c ) 4/3 -1/3 x 5/2

= 1 x 5/2

= 5/2

d) ( 3/2 - 3/8) : 1/2

= 9/8 : 1/2

= 9/4

e) 15/16 : 3/8 x 3/4 

= 5/2 x 3/4

= 15/8

f) 7/19 x 1/3 x 7/19 x 2/3

= 7/19 x (1/3 x 2/3)

= 7/19 x 2/9

= 14/171

g) 3/5 x 8/27 x 25/3

= 3/5 x 25/3 x 8/27 

= 5 x 8/27

= 40/27

h) 1/5 + 4/11 + 4/5 + 7/11

= (1/5 + 4/5) + (4/11 + 7/11)

= 1 + 1

= 2

2 tháng 8 2023

a) \(\dfrac{11}{3}-\dfrac{2}{3}\times\dfrac{5}{6}\)

\(=\dfrac{11}{3}-\dfrac{10}{18}\)

\(=\dfrac{11}{3}-\dfrac{5}{9}\)

\(=\dfrac{33}{9}-\dfrac{5}{9}\)

\(=\dfrac{28}{9}\)

b) \(\dfrac{13}{2}+\dfrac{7}{6}:\dfrac{2}{3}\)

\(=\dfrac{13}{2}+\dfrac{7}{6}\cdot\dfrac{3}{2}\)

\(=\dfrac{13}{2}+\dfrac{7}{4}\)

\(=\dfrac{26}{4}+\dfrac{7}{4}\)

\(=\dfrac{33}{4}\)

c) \(\dfrac{28}{9}-\dfrac{3}{4}+\dfrac{1}{3}\)

\(=\dfrac{28}{9}+\dfrac{3}{9}-\dfrac{3}{4}\)

\(=\dfrac{31}{9}-\dfrac{3}{4}\)

\(=\dfrac{124}{36}-\dfrac{27}{36}\)

\(=\dfrac{97}{36}\)

d) \(\dfrac{5}{8}:\dfrac{2}{3}\times\dfrac{1}{5}\)

\(=\dfrac{5}{8}\times\dfrac{3}{2}\times\dfrac{1}{5}\)

\(=\dfrac{15}{80}\)

\(=\dfrac{3}{16}\)

HQ
Hà Quang Minh
Giáo viên
2 tháng 8 2023

a) \(\dfrac{11}{3}-\dfrac{2}{3}\times\dfrac{5}{6}=\dfrac{11}{3}-\dfrac{5}{9}=\dfrac{28}{9}\)

b) \(\dfrac{13}{2}+\dfrac{7}{6}:\dfrac{2}{3}=\dfrac{13}{2}+\dfrac{7}{6}\times\dfrac{3}{2}=\dfrac{13}{2}+\dfrac{7}{4}=\dfrac{33}{4}\)

c) \(\dfrac{28}{9}-\dfrac{3}{4}+\dfrac{1}{3}=\dfrac{97}{36}\)

d) \(\dfrac{5}{8}:\dfrac{2}{3}\times\dfrac{1}{5}=\dfrac{5}{8}\times\dfrac{3}{2}\times\dfrac{1}{5}=\dfrac{3}{16}\)

20 tháng 3 2023

\(\dfrac{1}{2}\times\dfrac{3}{4}:\dfrac{6}{5}=\dfrac{3}{8}:\dfrac{6}{5}=\dfrac{5}{16}\)

\(\dfrac{2}{3}+\dfrac{1}{6}:\dfrac{7}{12}=\dfrac{2}{3}+\dfrac{2}{7}=\dfrac{14}{21}+\dfrac{6}{21}=\dfrac{20}{21}\)

\(8\times\dfrac{3}{5}:\dfrac{12}{5}=\dfrac{24}{5}:\dfrac{12}{5}=2\)

\(\dfrac{4}{9}+\dfrac{3}{4}-\dfrac{1}{3}=\dfrac{16}{36}+\dfrac{27}{36}-\dfrac{12}{36}=\dfrac{31}{36}\)

7 tháng 10 2018

viết đề lại ko hiểu

7 tháng 10 2018

Tách các phân số ra giùm cho nhờ cái

Đọc loạn cả r

Bây h đăng câu hỏi khác đi

Kiểu vt tách ra á

a: \(=\dfrac{1}{2}\cdot\dfrac{3}{4}\cdot\dfrac{5}{6}=\dfrac{15}{48}=\dfrac{5}{16}\)

b: \(=\dfrac{2}{3}+\dfrac{12}{42}=\dfrac{2}{3}+\dfrac{2}{7}=\dfrac{20}{21}\)

c: \(=\dfrac{24}{5}\cdot\dfrac{5}{12}=2\)

d: \(=\dfrac{1}{9}+\dfrac{3}{4}=\dfrac{4+27}{36}=\dfrac{31}{36}\)

12 tháng 7 2017

b1

a) \(\dfrac{1}{5.6}+\dfrac{1}{6.7}+\dfrac{1}{7.8}+\dfrac{1}{8.9}+\dfrac{1}{9.10}\)

\(=\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{10}\)

\(=\dfrac{1}{5}-\dfrac{1}{10}\)

\(=\dfrac{2}{10}-\dfrac{1}{10}\)

\(=\dfrac{1}{10}\)

b) \(\dfrac{1}{1.2}+\dfrac{1}{2.3}+...+\dfrac{1}{99.100}\)

\(=\dfrac{1}{1}-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{99}-\dfrac{1}{100}\)

\(=\dfrac{1}{1}-\dfrac{1}{100}\)

\(=\dfrac{99}{100}\)

c) \(\dfrac{2}{3.5}+\dfrac{2}{5.7}+\dfrac{2}{7.9}+\dfrac{2}{9.11}\)

\(=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{11}\)

\(=\dfrac{1}{3}-\dfrac{1}{11}\)

\(=\dfrac{8}{33}\)

d) \(\dfrac{2}{3.5}+\dfrac{2}{5.7}+...+\dfrac{2}{99.101}\)

\(=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+...+\dfrac{1}{99}-\dfrac{1}{101}\)

\(=\dfrac{1}{3}-\dfrac{1}{101}\)

\(=\dfrac{98}{303}\)

12 tháng 7 2017

ban lam bai 2 va 3 nua nha ♥♥♥

26 tháng 3 2019

\(\frac{2}{5}\times\frac{3}{8}+\frac{3}{4}=\frac{2\times3}{5\times8}+\frac{3}{4}=\frac{1\times3}{5\times4}+\frac{3}{4}=\frac{3}{20}+\frac{3}{4}=\frac{3}{20}+\frac{15}{20}=\frac{18}{20}=\frac{9}{10}\)

\(\frac{2}{5}+\frac{3}{8}\times\frac{3}{4}=\frac{2}{5}+\frac{9}{32}=\frac{64}{160}+\frac{45}{160}=\frac{109}{160}\)

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