a)\(\frac{4}{5}-\frac{1}{4}+\frac{3}{10}\)

\(=\frac{16}{20}-\frac{5}{20}+\frac{6}{20}\)

\(=\frac{17}{20}\)

b) \(\frac{2}{5}:\left(1-\frac{1}{10}\right)\)

\(=\frac{2}{5}:\frac{9}{10}\)

\(=\frac{4}{9}\)

c)\(\frac{7}{8}\times\frac{4}{9}+\frac{1}{14}:\frac{5}{14}\)

\(=\frac{7}{18}+\frac{1}{5}\)

\(=\frac{53}{90}\)

d)\(\frac{2}{7}\times\frac{3}{11}+\frac{2}{7}\times\frac{8}{11}\)

\(=\frac{2}{7}\times\left(\frac{3}{11}+\frac{8}{11}\right)\)

\(=\frac{2}{7}\times1=\frac{2}{7}\)

e) \(12+\left(16-11\right)\times4\)

\(=12+20=32\)

f)\(2\frac{3}{7}+1\frac{4}{7}\)

\(=\frac{17}{7}+\frac{11}{7}\)

\(=4\)

g)\(\frac{2}{3}\times\frac{4}{5}+\frac{1}{5}:\frac{9}{11}\)

\(=\frac{8}{15}+\frac{11}{45}\)

\(=\frac{7}{9}\)

h)\(\left(6,2:2+3,7\right):0,2\)

\(=\left(3,1+3,7\right):0,2\)

\(=6,8:0,2=34\)

#H

-4/11+5/6+7/11-5/6

=(-4/11+7/11)+(5/6-5/6)

=3/11+0

=3/11

Làm là giúp đủ 3 câu hộ mình. 1 câu k k đâu !

3/7*(0,5+11/2)-2/7:25%

=3/7*(0,5+11/2)-2/7:1/4

=3/7*(0,5+11/2)-2/7*4

=3/7*(1/2+11/2)-2/7*4

=3/7*6-2/7*4

=18/7-8/7

=10/7

a) \(\dfrac{7}{30}+\dfrac{\left(-12\right)}{37}+\dfrac{23}{30}+\dfrac{\left(-25\right)}{37}=\left(\dfrac{7}{30}+\dfrac{23}{30}\right)+\left(\dfrac{-12}{37}+\dfrac{-25}{37}\right)=1+\left(-1\right)=0\)

b) \(\dfrac{5}{7}\cdot\dfrac{5}{11}+\dfrac{5}{7}\cdot\dfrac{2}{11}-\dfrac{5}{7}\cdot\dfrac{14}{11}=\dfrac{5}{7}\cdot\left(\dfrac{5}{11}+\dfrac{2}{11}-\dfrac{14}{11}\right)=\dfrac{5}{7}\cdot\left(-\dfrac{7}{11}\right)=-\dfrac{5}{11}\)

c) \(\dfrac{\left(-5\right)}{7}\cdot\dfrac{3}{13}-\dfrac{5}{7}\cdot\dfrac{10}{13}+1\dfrac{5}{7}=\dfrac{5}{7}\cdot\dfrac{-3}{13}-\dfrac{5}{7}\cdot\dfrac{10}{13}+\dfrac{12}{7}=\dfrac{5}{7}\cdot\left(\dfrac{-3}{13}-\dfrac{10}{13}\right)+\dfrac{12}{7}=\dfrac{5}{7}\cdot\left(-1\right)+\dfrac{12}{7}=\left(-\dfrac{5}{7}\right)+\dfrac{12}{7}=\dfrac{7}{7}=1\)

cho mik xin bài giải với ạ

a) Ta có: BCNN(15,10) = 30 nên ta chọn mẫu số chung là 30

\(\frac{11}{15}+\frac{9}{10}=\frac{22}{30}+\frac{27}{30}=\frac{49}{30}\)

b) Ta có: BCNN(6,9,12) = 36 nên ta chọn mẫu số chung là 36

\(\frac{5}{6} + \frac{7}{9} + \frac{{11}}{{12}} = \frac{{30}}{{36}} + \frac{{28}}{{36}} + \frac{{33}}{{36}} = \frac{{91}}{{36}}\)

c) Ta có: BCNN(24,21) = 168 nên ta chọn mẫu số chung là 168

\(\frac{7}{{24}} - \frac{2}{{21}} = \frac{{49}}{{168}} - \frac{{16}}{{168}} = \frac{{33}}{{168}}=\frac{11}{56}\)

d) Ta có: BCNN(36,24) = 72 nên ta chọn mẫu số chung là 72

\(\frac{{11}}{{36}} - \frac{7}{{24}} = \frac{{22}}{{72}} - \frac{{21}}{{72}} = \frac{1}{{72}}\)

\(\frac{6}{11}\cdot\frac{3}{14}+\frac{-5}{16}+\frac{3}{14}\cdot\frac{5}{11}+\frac{-3}{16}\)

\(=\frac{6}{11}\cdot\frac{3}{14}+\frac{3}{14}\cdot\frac{5}{11}+\frac{-5}{16}+\frac{-3}{16}\)

\(=\frac{3}{14}\cdot\left(\frac{6}{11}+\frac{5}{11}\right)+\left(\frac{-5}{16}+\frac{-3}{16}\right)\)

\(=\frac{3}{14}\cdot\frac{6+5}{11}+\frac{-5+\left(-3\right)}{16}\)

\(=\frac{3}{14}\cdot\frac{11}{11}+\frac{-8}{16}\)

\(=\frac{3}{14}\cdot1+\frac{-1}{2}\)

\(=\frac{3}{14}+\frac{-1}{2}\)

\(=\frac{3}{14}+\frac{-7}{14}\)

\(=\frac{3+\left(-7\right)}{14}\)\(=\frac{-4}{14}=\frac{-2}{7}\)

\(\frac{-5}{6}+\left(7x-\frac{1}{2}\right)\cdot\frac{2}{9}=-1\frac{1}{3}\)

       \(\frac{-5}{6}+\frac{14}{9}\cdot x-\frac{1}{9}=-\frac{4}{3}\)

                       \(\frac{14}{9}\cdot x-\frac{1}{9}=-\frac{4}{3}+\frac{5}{6}\)

                       \(\frac{14}{9}\cdot x-\frac{1}{9}=-\frac{1}{2}\)

                                   \(\frac{14}{9}\cdot x=-\frac{1}{2}+\frac{1}{9}\)

                                   \(\frac{14}{9}\cdot x=-\frac{7}{18}\)

                                              \(x=-\frac{7}{18}:\frac{14}{9}\)

                                              \(x=-\frac{1}{4}\)

 đúng ko?