\(\dfrac{2}{-3}+\dfrac{7}{18}\)

\(\df...">

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\(a,\dfrac{2.6}{-3.6}+\dfrac{7}{18}=\dfrac{-12}{18}+\dfrac{7}{18}=\dfrac{5}{18}\\ b,\dfrac{1.2}{2.2}+\dfrac{-4}{3}=\dfrac{2}{4}.\dfrac{-4}{3}=\dfrac{-8}{12}=\dfrac{-2}{3}\)

2 tháng 2 2022

Very good

15 tháng 5 2017

Trả lời:

Phép cộng phân số

a: \(=\dfrac{-28}{36}+\dfrac{15}{36}-\dfrac{26}{36}=\dfrac{-39}{36}=\dfrac{-13}{12}\)

b: \(=\dfrac{11}{9}\left(\dfrac{15}{4}-\dfrac{7}{4}-\dfrac{5}{4}\right)=\dfrac{11}{9}\cdot\dfrac{3}{4}=\dfrac{11}{12}\)

c: \(=15+\dfrac{9}{7}+6+\dfrac{2}{3}-5-\dfrac{5}{9}\)

\(=16+\dfrac{88}{63}=\dfrac{1096}{63}\)

d: \(=\dfrac{5}{6}-\dfrac{1}{3}+\dfrac{2}{18}\)

\(=\dfrac{15-6+2}{18}=\dfrac{11}{18}\)

22 tháng 3 2017

\(a)\dfrac{3}{4}-\dfrac{-5}{2}-\dfrac{7}{-24}\)

\(=\dfrac{13}{4}-\dfrac{7}{-24}\)

\(=\dfrac{85}{24}\)

\(b)\dfrac{4}{7}+\dfrac{-5}{8}-\dfrac{3}{28}\)

\(=\dfrac{-3}{56}-\dfrac{3}{28}\)

\(=\dfrac{-9}{56}\)

\(c)\dfrac{7}{36}-\dfrac{8}{-9}+\dfrac{-2}{3}\)

\(=\dfrac{13}{12}\)\(+\dfrac{-2}{3}\)

\(=\dfrac{5}{12}\)

\(d)\dfrac{-1}{2}+\dfrac{3}{7}-\dfrac{1}{9}+\dfrac{-7}{18}+\dfrac{4}{7}\)

\(=\dfrac{-1}{14}-\dfrac{1}{9}+\dfrac{-7}{18}+\dfrac{4}{7}\)

\(=\dfrac{-23}{126}+\dfrac{-7}{18}+\dfrac{4}{7}\)

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

\(=0\)

\(e)\dfrac{2}{7}+\dfrac{-3}{8}+\dfrac{11}{7}+\dfrac{1}{3}+\dfrac{1}{7}+\dfrac{5}{-8}\)

\(=\dfrac{-5}{56}+\dfrac{11}{7}+\dfrac{1}{3}+\dfrac{1}{7}+\dfrac{5}{-8}\)

\(=\dfrac{83}{56}+\dfrac{1}{3}+\dfrac{1}{7}+\dfrac{5}{-8}\)

\(=\dfrac{305}{168}+\dfrac{1}{7}+\dfrac{5}{-8}\)

\(=\dfrac{47}{24}+\dfrac{5}{-8}\)

\(=\dfrac{4}{3}\)

22 tháng 3 2017

Bài 2 : Tính

a) \(\dfrac{3}{4}-\dfrac{-5}{2}-\dfrac{7}{-24}\)

\(=\dfrac{18}{24}-\dfrac{-60}{24}-\dfrac{-4}{24}\)

\(=\dfrac{18-\left(-60\right)-\left(-7\right)}{24}\)

\(=\dfrac{85}{24}\)

b) \(\dfrac{4}{7}+\dfrac{-5}{8}-\dfrac{3}{28}\)

\(=\dfrac{32}{56}+\dfrac{-35}{56}-\dfrac{6}{56}\)

\(=\dfrac{32+\left(-35\right)-6}{56}\)

\(=\dfrac{-9}{56}\)

c) \(\dfrac{7}{36}-\dfrac{8}{9}+\dfrac{-2}{3}\)

\(=\dfrac{7}{36}-\dfrac{32}{36}+\dfrac{-24}{36}\)

\(=\dfrac{7-32+\left(-24\right)}{36}\)

\(=\dfrac{-49}{36}\)

d) \(\dfrac{-1}{2}+\dfrac{3}{7}-\dfrac{1}{9}+\dfrac{-7}{18}+\dfrac{4}{7}\)

\(=\dfrac{-9}{18}+\dfrac{3}{7}-\dfrac{2}{18}+\dfrac{-7}{18}+\dfrac{4}{7}\)

\(=\left(\dfrac{-9}{18}+\dfrac{-7}{18}-\dfrac{2}{18}\right)+\left(\dfrac{3}{7}+\dfrac{4}{7}\right)\)

\(=\left(-1\right)+1\)

\(=0\)

e) \(\dfrac{2}{7}+\dfrac{-3}{8}+\dfrac{11}{7}+\dfrac{1}{3}+\dfrac{1}{7}+\dfrac{5}{-8}\)

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

\(=2+\left(-1\right)+\dfrac{1}{3}\)

\(=1+\dfrac{1}{3}\)

\(=\dfrac{4}{3}\)

Đề răng dài thế này thì tui giải từng câu hí

a) \(\dfrac{-7}{9}+\dfrac{5}{12}-\dfrac{13}{18}\left(MSC:36\right)\)

\(=\dfrac{-28}{36}+\dfrac{15}{36}-\dfrac{26}{36}\)

\(=\dfrac{-13}{36}-\dfrac{26}{36}\)

\(=\dfrac{-39}{36}\)

\(=\dfrac{13}{3}\)

b) \(\dfrac{11}{9}.\dfrac{15}{4}-\dfrac{11}{4}.\dfrac{7}{9}-\dfrac{11}{9}.\dfrac{5}{4}\)

\(=\left(\dfrac{15}{4}-\dfrac{11}{4}-\dfrac{5}{4}\right).\dfrac{11}{9}\)

\(=\left(1-\dfrac{5}{4}\right).\dfrac{11}{9}\)

\(=\left(\dfrac{4}{4}-\dfrac{5}{4}\right).\dfrac{11}{9}\)

\(=\dfrac{-1}{4}.\dfrac{11}{9}\)

\(=\dfrac{-11}{36}\)

a: Sai

b: Đúng

c: Sai

a: \(A=\left(\dfrac{-3}{4}+\dfrac{-2}{9}-\dfrac{1}{36}\right)+\left(\dfrac{1}{3}+\dfrac{1}{15}+\dfrac{3}{5}\right)+\dfrac{1}{57}\)

\(=\dfrac{-27-8-1}{36}+\dfrac{5+1+9}{15}+\dfrac{1}{57}\)

=1/57

b: \(B=\left(\dfrac{1}{2}+\dfrac{1}{6}+\dfrac{1}{3}\right)+\left(\dfrac{-1}{5}-\dfrac{5}{7}-\dfrac{3}{35}\right)+\dfrac{1}{41}\)

\(=\dfrac{3+1+2}{6}+\dfrac{-7-25-3}{35}+\dfrac{1}{41}\)

=1/41

c: \(C=\left(\dfrac{-1}{2}-\dfrac{1}{9}-\dfrac{7}{18}\right)+\left(\dfrac{3}{5}+\dfrac{2}{7}+\dfrac{4}{35}\right)+\dfrac{1}{107}\)

=1-1+1/107

=1/107

16 tháng 4 2017

Giải bài 42 trang 26 SGK Toán 6 Tập 2 | Giải toán lớp 6

17 tháng 4 2017

a. \(\dfrac{-3}{5}\)

b. \(\dfrac{-2}{3}\) c. \(\dfrac{4}{39}\) d. \(\dfrac{26}{45}\)

17 tháng 4 2017

a) ; b) ; c) ; d) ; e) ; g) .

1 tháng 5 2018

Giải bà i 69 trang 36 SGK Toán 6 Tập 2 | Giải toán lá»p 6

2 tháng 3 2018

\(a.\dfrac{3}{5}-\dfrac{-7}{10}-\dfrac{13}{-20}=\dfrac{12}{20}-\dfrac{-14}{20}-\dfrac{-13}{20}=\dfrac{12-\left(-14\right)-\left(-13\right)}{20}=\dfrac{39}{20}\)

\(b.\dfrac{3}{4}+\dfrac{-1}{3}-\dfrac{5}{18}=\dfrac{3}{4}+\left(\dfrac{-6}{18}-\dfrac{5}{18}\right)=\dfrac{3}{4}+\dfrac{-11}{18}=\dfrac{27}{36}-\dfrac{-22}{36}=\dfrac{49}{36}\)

\(c.\dfrac{3}{13}-\dfrac{5}{-8}+\dfrac{-1}{2}=\dfrac{3}{13}-\left(\dfrac{5}{-8}+\dfrac{-4}{8}\right)=\dfrac{3}{13}-\dfrac{1}{8}=\dfrac{24}{104}-\dfrac{13}{104}=\dfrac{11}{104}\)

\(d.\dfrac{1}{2}+\dfrac{1}{-3}=\dfrac{3}{6}+\dfrac{-2}{6}=\dfrac{1}{6}\)

2 tháng 3 2018

\(a,\dfrac{3}{5}-\dfrac{-7}{10}-\dfrac{13}{-20}\)

\(=\dfrac{12}{20}+\dfrac{14}{20}+\dfrac{13}{20}\)

\(=\dfrac{12+14+13}{20}\)

\(=\dfrac{39}{20}\)

\(b,\dfrac{3}{4}+\dfrac{-1}{3}-\dfrac{5}{18}\)

\(=\dfrac{27}{36}+\dfrac{-12}{36}-\dfrac{10}{36}\)

\(=\dfrac{27+\left(-12\right)-10}{36}\)

\(=\dfrac{5}{36}\)

\(c,\dfrac{3}{13}-\dfrac{5}{-8}+\dfrac{-1}{2}\)

\(=\dfrac{24}{104}-\dfrac{-65}{104}+\dfrac{-52}{104}\)

\(=\dfrac{24-\left(-65\right)+\left(-52\right)}{104}\)

\(=\dfrac{37}{104}\)

\(d,\dfrac{1}{2}+\dfrac{1}{-3}\)

\(=\dfrac{3}{6}+\dfrac{-2}{6}\)

\(=\dfrac{3+\left(-2\right)}{6}\)

\(=\dfrac{1}{6}\)