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16 tháng 6 2017

Mẫu số chung là BCNN(14 ; 8 ; 2) = 56.

Giải bài 107 trang 48 SGK Toán 6 Tập 2 | Giải toán lớp 6

 

3 tháng 8 2015

a, \(\frac{-3}{7}+\frac{5}{13}-\frac{4}{7}+\frac{8}{13}\)

\(=\frac{-3}{7}-\frac{4}{7}+\frac{5}{13}+\frac{8}{13}\)

\(=-\frac{7}{7}+\frac{13}{13}=-1+1=0\)

b, \(\frac{-5}{14}-\frac{2}{-14}+\frac{1}{8}+\frac{1}{8}\)

\(=\frac{-5}{14}+\frac{2}{14}+\frac{1}{8}+\frac{1}{8}\)

\(=-\frac{3}{14}+\frac{1}{4}=\frac{1}{28}\)

c,\(-\frac{5}{13}-\left(\frac{3}{5}+\frac{3}{13}-\frac{4}{10}\right)\)

\(=-\frac{5}{13}-\frac{3}{13}-\frac{3}{5}+\frac{4}{10}\)

\(=-\frac{8}{13}-\frac{3}{5}+\frac{4}{10}=-\frac{79}{65}+\frac{4}{10}=-\frac{53}{65}\)

d, \(\left[\left(\frac{1}{8}-\frac{9}{7}+\frac{4}{6}-\frac{12}{7}-\frac{1}{2}\right)+\frac{5}{9}\right]\)

\(=\left[\left(\frac{1}{8}-\frac{9}{7}+\frac{2}{3}-\frac{12}{7}-\frac{1}{2}\right)+\frac{5}{9}\right]\)

\(=\left[\left(\frac{1}{8}-\frac{1}{2}-\frac{9}{7}-\frac{12}{7}+\frac{2}{3}\right)+\frac{5}{9}\right]\)

\(=-\frac{65}{24}+\frac{5}{9}=-2\frac{11}{72}\)

 

12 tháng 2 2023

\(a,\dfrac{4}{5}+\dfrac{2}{3}+\dfrac{1}{9}=\dfrac{12}{15}+\dfrac{10}{15}+\dfrac{1}{9}=\dfrac{22}{15}+\dfrac{1}{9}=\dfrac{66}{45}+\dfrac{5}{45}=\dfrac{71}{45}\)

\(b,\dfrac{3}{7}+\dfrac{11}{14}+\dfrac{19}{28}=\dfrac{12}{28}+\dfrac{22}{28}+\dfrac{19}{28}=\dfrac{53}{28}\)

\(c,\dfrac{1}{2}+\dfrac{1}{7}+\dfrac{-1}{5}=\dfrac{7}{14}+\dfrac{2}{14}+\dfrac{-1}{5}=\dfrac{9}{14}+\dfrac{-1}{5}=\dfrac{45}{70}+\dfrac{-14}{70}=\dfrac{31}{70}\)

\(d,\dfrac{7}{8}+\dfrac{5}{16}+\dfrac{-3}{4}=\dfrac{14}{16}+\dfrac{5}{16}+\dfrac{-12}{16}=\dfrac{7}{16}\)

\(e,\dfrac{1}{4}+\dfrac{5}{12}+\dfrac{-1}{13}=\dfrac{3}{12}+\dfrac{5}{12}+\dfrac{-1}{13}=\dfrac{8}{12}+\dfrac{-1}{13}=\dfrac{2}{3}+\dfrac{-1}{13}=\dfrac{26}{39}+\dfrac{-3}{39}=\dfrac{23}{39}\)

\(g,\dfrac{2}{3}+\dfrac{3}{8}+\dfrac{-5}{12}=\dfrac{16}{24}+\dfrac{9}{24}+\dfrac{-5}{12}=\dfrac{25}{24}+\dfrac{-5}{12}=\dfrac{25}{24}+\dfrac{-10}{24}=\dfrac{15}{24}\)

13 tháng 2 2023

de ma

 

18 tháng 3 2022

Gợi ý: Nó trong VBT Toán Nâng Cao

27 tháng 2 2023

bó tay !

 

10 tháng 5 2023

`7 xx 3/14 -1/14`

`= 21/14 -1/14`

`= 20/14`

`=10/7`

__

`3/2 + 7/4 xx 2/5`

`= 3/2 + 14/20`

`= 3/2 + 7/10`

`= 15/10 +7/10`

`= 23/10`

__

`9/8 : 3 + 7/3 : 3`

`= 9/8 xx 1/3 + 7/3 xx 1/3`

`=1/3 xx ( 9/8 + 7/3)`

`= 1/3 xx 83/24`

`= 83/72`

__

`2 : 3/4 - 5/8 xx 4/3`

`= 2 xx 4/3 - 5/8 xx 4/3`

`= 4/3 xx ( 2-5/8)`

`= 4/3 xx ( 16/8 -5/8)`

`= 4/3 xx 11/8`

`= 44/24`

`=11/6`

` @ \color{Red}{sushiteam}`

13 tháng 4 2019

a= 7/5

b=28/63

c=5/8

d=4/15

13 tháng 4 2019

\(a)\frac{3}{8}+\frac{2}{5}+\frac{5}{8}=\left(\frac{3}{8}+\frac{5}{8}\right)+\frac{2}{5}=1+\frac{2}{5}=\frac{7}{5}\)

\(b)\frac{5}{7}.\frac{2}{3}.\frac{14}{15}=\frac{5.2.14}{7.3.15}=\frac{4}{9}\)

\(c)\frac{3}{8}+\frac{2}{5}.\frac{5}{8}=\frac{3}{8}+\frac{1}{4}=\frac{3}{8}+\frac{2}{8}=\frac{5}{8}\)

\(d)\frac{11}{15}-\left(\frac{2}{3}-\frac{1}{5}\right)=\frac{11}{15}-\frac{7}{15}=\frac{4}{15}\)

~Học tốt~

13 tháng 4 2019

\(a)\frac{3}{8}+\frac{2}{5}+\frac{5}{8}=\left(\frac{3}{8}+\frac{5}{8}\right)+\frac{2}{5}=1+\frac{2}{5}=\frac{7}{5}\)

\(b)\frac{5}{7}.\frac{2}{3}.\frac{14}{15}=\frac{5.2.14}{7.3.15}=\frac{4}{9}\)

\(c)\frac{3}{8}+\frac{2}{5}.\frac{5}{8}=\frac{3}{8}+\frac{1}{4}=\frac{3}{8}+\frac{2}{8}=\frac{5}{8}\)

\(d)\frac{11}{15}-\left(\frac{2}{3}-\frac{1}{5}\right)=\frac{11}{15}-\frac{7}{15}=\frac{4}{15}\)

~Học tốt~

13 tháng 4 2019

a) \(\frac{3}{8}+\frac{2}{5}+\frac{5}{8}=\frac{3}{8}+\frac{5}{8}+\frac{2}{5}=\frac{3+5}{8}+\frac{2}{5}\)

\(=1+\frac{2}{5}=\frac{5}{5}+\frac{2}{5}=\frac{7}{5}\)

b) \(\frac{5}{7}\times\frac{2}{3}\times\frac{14}{15}=\frac{5}{7}\times\frac{14}{15}\times\frac{2}{3}=\frac{5\times2\times7}{7\times3\times5}\times\frac{2}{3}\)

\(=\frac{2}{3}\times\frac{2}{3}=\frac{4}{9}\)

c) \(\frac{3}{8}+\frac{2}{5}\times\frac{5}{8}=\frac{3}{8}+\frac{2\times5}{5\times8}=\frac{3}{8}+\frac{2}{8}\)

\(=\frac{5}{8}\)

d) \(\frac{11}{15}-\left(\frac{2}{3}-\frac{1}{5}\right)=\frac{11}{15}-\frac{2}{3}+\frac{1}{5}=\frac{11}{15}-\frac{2\times5}{3\times5}+\frac{3\times1}{3\times5}\)

\(=\frac{11}{15}-\frac{10}{15}+\frac{3}{15}=\frac{11-10+3}{15}=\frac{4}{15}\)

15 tháng 8 2019

\(A=\frac{2}{7}+\frac{-3}{8}+\frac{11}{7}+\frac{1}{3}+\frac{1}{7}+\frac{5}{-8}\)

\(A=\left(\frac{2}{7}+\frac{11}{7}+\frac{1}{7}\right)+\left(\frac{-3}{8}+\frac{5}{-8}\right)+\frac{1}{3}\)

\(A=2-1+\frac{1}{3}\)

\(A=\frac{4}{3}\)

\(B=\frac{3}{17}+\frac{-5}{13}+\frac{-18}{35}+\frac{14}{17}+17\)

\(B=\left(\frac{3}{17}+\frac{14}{17}\right)+\frac{-5}{13}+\frac{-18}{35}+17\)

\(B=1+\frac{-5}{13}+\frac{-18}{35}+17\)

\(B=18+\frac{-5}{13}+\frac{-18}{35}\)

\(B=\frac{7781}{455}\)

a: =6/10+35/10=41/10

b: =126/9-1/9=125/9

c: =12/2=6

d: =7/8*1/5=7/40

17 tháng 12 2021

bai EZ​ quabanh

25 tháng 12 2021

????

:))))