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19 tháng 2 2022

Đề bài là gì nhỉ ?

19 tháng 2 2022

quy đồng mẫu số 

 

a: 7/4=28/16

15/16=15/16

b: 1/8=3/24

2/3=16/24

5/2=60/24

c: 2/7=8/28

9/4=63/28

5/28=5/28

19 tháng 2 2022

a)\(28/16 và 15/16\)

b)\(3/24; 16/24; 60/24\)

c)\(8/28; 63/28; 5/28\)nhé 

8 tháng 6 2020

Bài làm

a) \(\left(\frac{3}{8}+\frac{-1}{4}+\frac{5}{12}\right):\frac{2}{3}\)

\(=\left(\frac{9}{24}+\frac{-6}{24}+\frac{10}{24}\right).\frac{3}{2}\)

\(=\frac{13}{24}.\frac{3}{2}\)

\(=\frac{39}{48}\)

b) \(\frac{-5}{7}.\frac{2}{11}+\frac{-5}{7}.\frac{9}{11}+1\frac{5}{7}\)

\(=-\frac{5}{7}.\left(\frac{2}{11}+\frac{9}{11}\right)+\frac{12}{7}\)

\(=-\frac{5}{7}.1+\frac{12}{7}\)

\(=\frac{7}{7}\)

\(=1\)

c) \(0,25:\left(10,3-9,8\right)-\frac{3}{4}\)

\(=\frac{25}{100}:\left(0,5\right)-\frac{3}{4}\)

\(=\frac{5}{4}:\frac{1}{2}-\frac{3}{4}\)

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

\(=\frac{5}{2}-\frac{3}{4}\)

\(=\frac{10}{4}-\frac{3}{4}=\frac{7}{4}\)

d) \(-\frac{5}{9}.\frac{13}{28}-\frac{13}{28}.\frac{4}{9}\)

\(=-\frac{13}{28}\left(\frac{5}{9}+\frac{4}{9}\right)\)

\(=-\frac{13}{28}.\frac{9}{9}\)

\(=-\frac{13}{28}.1\)

\(=-\frac{13}{28}\)

14 tháng 8 2017

a, (5/7+ 2/7) + ( 3/8+5/8)

= 1              + 1

27 tháng 9

Bài 1:

a; \(\dfrac{7}{8}\) + \(x\) = \(\dfrac{4}{7}\)

     \(x\) = \(\dfrac{4}{7}\) - \(\dfrac{7}{8}\)

     \(x\) = \(\dfrac{32}{56}\) - \(\dfrac{49}{56}\)

     \(x=-\) \(\dfrac{49}{56}\)

Vậy \(x=-\dfrac{49}{56}\)

b; 6 - \(x\) = - \(\dfrac{3}{4}\)

         \(x\) = 6 + \(\dfrac{3}{4}\)

         \(x\) = \(\dfrac{24}{4}+\dfrac{3}{4}\)

         \(x=\dfrac{27}{4}\)

Vậy \(x=\dfrac{27}{4}\) 

c; \(\dfrac{1}{-5}\) + \(x\) = \(\dfrac{3}{4}\)

              \(x\) = \(\dfrac{3}{4}\) + \(\dfrac{1}{5}\)

              \(x=\dfrac{15}{20}\) + \(\dfrac{4}{20}\)

               \(x=\dfrac{19}{20}\)

Vậy \(x=\dfrac{19}{20}\) 

27 tháng 9

      Bài 1:

d; - 6 - \(x\) = - \(\dfrac{3}{5}\)

      \(x\)   = - 6 + \(\dfrac{3}{5}\)

       \(x=-\dfrac{30}{5}\) + \(\dfrac{3}{5}\)

       \(x=-\dfrac{27}{5}\)

Vậy \(x=-\dfrac{27}{5}\)

e; - \(\dfrac{2}{6}\) + \(x\) = \(\dfrac{5}{7}\)

             \(x\) = \(\dfrac{5}{7}\) + \(\dfrac{2}{6}\)

             \(x\) = \(\dfrac{15}{21}\) + \(\dfrac{1}{3}\)

              \(x=\dfrac{15}{21}\) + \(\dfrac{7}{21}\)

               \(x=\dfrac{22}{21}\)

Vậy \(x=\dfrac{22}{21}\) 

f; - 8 - \(x\) =  - \(\dfrac{5}{3}\)

          \(x\) = \(-\dfrac{5}{3}\) + 8

         \(x\) = \(\dfrac{-5}{3}\) + \(\dfrac{24}{3}\)

         \(x\) = \(\dfrac{-19}{3}\)

Vậy \(x=-\dfrac{19}{3}\) 

 

            

 

2 tháng 7 2018

A) 137/ 12

B) 4

C) 5

2 tháng 7 2018

b, 3/5 + 4/7 + 2/8 + 10/25 + 9/21 + 28/16

= 3/5 + 4/7 + 2/8 + 2/5 + 3/7 + 14/8

= (3/5 + 2/5) + ( 4/7 + 3/7) + ( 2/8 + 14/8)

= 1 + 1 + 7/4

= 2 + 7/4 = 15/4

c , 8/7 + 7/6 + 5/8 + 10/12 + 24/28 + 6/16 

= c , 8/7 + 7/6 + 5/8 + 5/6 + 6/7 + 1/2

= (8/7 + 6/7) + (7/6 + 5/6) + 5/8 + 1/2

= 14/7 + 12/6 + 5/8 + 1/2

= 2 + 2 + 5/8 + 1/2

= 4 + 9/8 = 41/8

25 tháng 2 2019

\(a)9+\frac{24}{25}=\frac{9\cdot25+24}{25}=\frac{249}{25}\)

\(b)\frac{1}{20}+\frac{1}{4}+\frac{2}{5}=\frac{1}{20}+\frac{5}{20}+\frac{8}{20}=\frac{1+5+8}{20}=\frac{14}{20}=\frac{7}{10}\)

\(c)\frac{7}{12}+4=\frac{7}{12}+\frac{4}{1}=\frac{7+48}{12}=\frac{55}{12}\)

\(d)10+\frac{9}{8}=\frac{10}{1}+\frac{9}{8}=\frac{80+9}{8}=\frac{89}{8}\)

\(e)\frac{1}{4}+\frac{2}{25}+\frac{9}{100}=\frac{25}{100}+\frac{8}{100}+\frac{9}{100}=\frac{25+8+9}{100}=\frac{42}{100}=\frac{21}{50}\)

Còn 3 câu làm tương tự

25 tháng 2 2019

Ba câu còn lại mình làm luôn :D

\(f)\frac{28}{90}+6=\frac{14}{45}+6=\frac{14}{45}+\frac{6}{1}=\frac{14+270}{45}=\frac{284}{45}\)

\(g)\frac{3}{7}+\frac{4}{9}+\frac{4}{7}+\frac{7}{11}=(\frac{3}{7}+\frac{4}{7})+\frac{4}{9}+\frac{4}{11}=1+\frac{4}{9}+\frac{4}{11}\)

\(=\frac{7}{7}+\frac{4}{9}+\frac{4}{11}=\frac{693+308+252}{693}=\frac{1253}{693}=\frac{179}{99}\)

\(h)\frac{1}{8}+\frac{1}{12}+\frac{3}{8}+\frac{5}{12}=(\frac{1}{8}+\frac{3}{8})+(\frac{1}{12}+\frac{5}{12})=\frac{4}{8}+\frac{6}{12}=\frac{1}{2}+\frac{1}{2}=1\)

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

a: \(=\dfrac{2}{3}+\dfrac{19}{35}=\dfrac{70+57}{105}=\dfrac{127}{105}\)

b: \(=\dfrac{2}{7}+\dfrac{2}{5}=\dfrac{24}{35}\)

c: \(=\dfrac{7}{12}-\dfrac{14}{2}=\dfrac{7-84}{12}=\dfrac{-77}{12}\)

d: \(=\dfrac{-15}{60}-\dfrac{1}{8}=-\dfrac{3}{8}\)

e: \(=-\dfrac{12}{72}+\dfrac{1}{18}=\dfrac{-3}{18}+\dfrac{1}{18}=\dfrac{-2}{18}=\dfrac{-1}{9}\)