(-1/4+7/33-5/3)-(-5/12+6/11-5/42)

=-1/4+7/33-5/3-5/12-6/11+5/42

=-1/4-5/12+7/33-6/11-5/3+5/42

=-8/12+(-3/11)-25/12

=-8/12-25/12+(-3/11)

=-33/12+-3/11

=-11/4+-3/11

=-133/44

Mk làm sai rồi !

\(\left(\frac{-1}{4}+\frac{7}{33}-\frac{5}{3}\right)-\left(\frac{-5}{12}+\frac{6}{11}-\frac{5}{42}\right)\)

\(=\frac{-1}{4}+\frac{7}{33}-\frac{5}{3}+\frac{5}{12}-\frac{6}{11}+\frac{5}{42}\)

\(=\left(\frac{5}{12}-\frac{1}{4}\right)-\left(\frac{5}{3}-\frac{5}{42}\right)-\left(\frac{6}{11}-\frac{7}{33}\right)\)

\(=\frac{1}{6}-\frac{65}{42}-\frac{1}{3}\)

\(=\frac{-29}{21}-\frac{1}{3}\)

\(=\frac{-12}{7}\)

\(\left(\frac{-1}{4}+\frac{7}{33}-\frac{5}{3}\right)-\left(\frac{-5}{12}+\frac{6}{11}-\frac{5}{42}\right)\)

\(=-\frac{1}{4}+\frac{7}{33}-\frac{5}{3}+\frac{5}{12}-\frac{6}{11}+\frac{5}{42}\)

\(=\frac{5-3}{12}+\frac{7-18}{33}+\frac{5+70}{42}=\frac{1}{6}-\frac{1}{3}+\frac{65}{42}\)

\(\left(\frac{-1}{4}+\frac{7}{33}-\frac{5}{3}\right)-\left(\frac{-5}{4}+\frac{6}{11}-\frac{48}{49}\right)=\left(\frac{-1}{4}-\frac{16}{11}\right)-\left(-\frac{31}{44}-\frac{48}{49}\right)=-\frac{1}{4}-\frac{16}{11}+\frac{31}{44}+\frac{48}{49}=-\frac{1}{49}\)

bai de the ma cung hoi

a) \(-\frac{1}{4}.13\frac{9}{11}-0,25.6\frac{2}{11}\)

\(=-\frac{1}{4}.13\frac{9}{11}-\frac{1}{4}.6\frac{2}{11}\)

\(=-\frac{1}{4}\left(13\frac{9}{11}+6\frac{2}{11}\right)\)

\(=-\frac{1}{4}.20\)

\(=-5\)

b) \(B=\frac{-5}{6}.\frac{4}{19}+\frac{-7}{12}.\frac{4}{19}-\frac{40}{57}\)

\(=\frac{4}{19}\left(\frac{-5}{6}+\frac{-7}{12}\right)-\frac{40}{57}\)

\(=\frac{4}{19}.\frac{-17}{12}-\frac{40}{57}\)

\(=\frac{-17}{57}-\frac{40}{57}\)

\(=-1\)

c)  \(\frac{3}{7}.\frac{9}{26}-\frac{1}{14}.\frac{1}{13}-\frac{1}{7}\)

\(=\frac{3}{7}.\frac{9}{26}-\frac{1}{2}.\frac{1}{7}.\frac{1}{13}-\frac{1}{7}\)

\(=\frac{1}{7}\left(3.\frac{9}{26}-\frac{1}{2}.\frac{1}{13}-1\right)\)

\(=\frac{1}{7}.0\)

\(=0\)

d) \(\frac{4}{9}:\left(-\frac{1}{7}\right)+6\frac{5}{9}:\left(-\frac{1}{7}\right)\)

\(=\left(\frac{4}{9}+6\frac{5}{9}\right):\left(-\frac{1}{7}\right)\)

\(=7:\left(-\frac{1}{7}\right)\)

\(=-49\)

\(A=-\frac{1}{4}x3\frac{9}{11}-0,25x6\frac{2}{11}\)

\(A=-0,25x3\frac{9}{11}-0,25x6\frac{2}{11}\)

\(A=-0,25x\left(\frac{9}{11}+\frac{2}{11}\right)\)

\(A=-0,25x1\)

\(A=-0,25\)

\(B=-\frac{5}{6}x\frac{4}{19}+-\frac{7}{12}x\frac{4}{19}-\frac{40}{57}\)

\(B=-\frac{5}{6}x\frac{4}{19}+-\frac{7}{12}x\frac{4}{19}-\frac{4}{19}x190\)

\(B=\frac{4}{19}x\left(-\frac{5}{6}-\frac{7}{12}-190\right)\)

\(B=\frac{4}{19}x\left(-\frac{2297}{12}\right)\)

\(B=\frac{-2297}{57}\)

\(C=\frac{3}{7}x\frac{9}{26}-\frac{1}{14}x\frac{1}{13}-\frac{1}{7}\)

\(C=\frac{1}{7}x3x\frac{9}{26}-\frac{1}{7}x\frac{1}{2}x\frac{1}{13}-\frac{1}{7}\)

\(C=\frac{1}{7}x\left(3x\frac{9}{26}-\frac{1}{2}x\frac{1}{13}-1\right)\)

\(C=\frac{1}{7}x0\)

\(C=\frac{1}{7}\)

\(D=\frac{4}{9}:\left(-\frac{1}{7}\right)+6\frac{5}{9}:\left(-\frac{1}{7}\right)\)

\(D=\left(\frac{4}{9}+6\frac{5}{9}\right):\left(-\frac{1}{7}\right)\)

\(D=7:\left(-\frac{1}{7}\right)\)

\(D=-49\)

bài 1:

\(\frac{6}{11}+\frac{1}{3}+\frac{5}{11}\)

\(=\left(\frac{6}{11}+\frac{5}{11}\right)+\frac{1}{3}\)

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

bài 2:

\(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}\)

\(=\left(\frac{1}{2}+\frac{1}{20}\right)+\left(\frac{1}{6}+\frac{1}{12}\right)\)

\(=\frac{11}{20}+\frac{1}{4}=\frac{11}{20}+\frac{5}{20}=\frac{15}{20}=\frac{3}{4}\)

bài 3: 

a) \(\frac{3}{2}\cdot\frac{4}{5}\cdot\frac{2}{3}=\left(\frac{3}{2}\cdot\frac{2}{3}\right)\cdot\frac{4}{5}=1\cdot\frac{4}{5}=\frac{4}{5}\)

b) \(\frac{6}{7}\cdot\frac{5}{3}\cdot\frac{7}{6}=\left(\frac{6}{7}\cdot\frac{7}{6}\right)\cdot\frac{5}{3}=1\cdot\frac{5}{3}=\frac{5}{3}\)

bài 4: 

a) \(\frac{2}{5}\cdot\frac{1}{4}+\frac{3}{4}\cdot\frac{2}{5}=\frac{2}{5}\cdot\left(\frac{1}{4}+\frac{3}{4}\right)=\frac{2}{5}\cdot1=\frac{2}{5}\)

b) \(\frac{6}{11}:\frac{2}{3}+\frac{5}{11}:\frac{2}{3}=\left(\frac{6}{11}+\frac{5}{11}\right):\frac{2}{3}=1:\frac{2}{3}=\frac{3}{2}\)

Bài 1: 

  6/11 + 1/3 + 5/11 

= ( 6/11 + 5/11) + 1/3

= 11/11 + 1/3

= 1 + 1/3 

= 3/3 +1/3  

= 4/3 

Bài 2: 

1/2 + 1/6 + 1/12 + 1/20 

= ( 1/2 + 1/6 + 1/12 ) + 1/20 

= ( 6/12 + 2/12 + 1/12 ) + 1/20 

=9/12 + 1/20 

= 3/4 +1/20  

= 15/20 + 1/20 

= 16/20 = 4/5

 Bài 3:

a) \(\frac{3}{2}\times\frac{4}{5}\times\frac{2}{3}\) \(=\left(\frac{3}{2}\times\frac{2}{3}\right)\times\frac{4}{5}\)\(=1\times\frac{4}{5}=\frac{4}{5}\) 

b)  \(\frac{6}{7}\times\left(\frac{5}{3}\times\frac{7}{6}\right)\) \(=\frac{6}{7}\times\frac{35}{18}\)\(=\frac{1\times5}{7\times3}=\frac{5}{21}\)   

Bài 4:

a) 2/5  x 1/4 + 3/4 x 2/5 

= 2/5 x ( 1/4  + 3/4) 

 = 2/5 x  1 

= 2/5

 b) 6/11 : 2/3 +5/11 : 2/3 

=  ( 6/11 + 5/11) x 3/2 

= 11/11 x 3/2  

= 1 x 3/2  

=  3/2  

....  

\(9\frac{2}{9}+\frac{2}{3}+7\frac{7}{9}\)

\(=9+\frac{2}{9}+\frac{2}{3}+7+\frac{7}{9}\)

\(=\left(9+7\right)+\left(\frac{2}{9}+\frac{7}{9}\right)+\frac{2}{3}\)

\(=16+1+\frac{2}{3}\)

\(=17+\frac{2}{3}\)

\(=\frac{51}{3}+\frac{2}{3}\)

\(=\frac{53}{3}\)

\(\frac{5}{9}.\frac{10}{11}+\frac{5}{9}.\frac{14}{11}-\frac{5}{9}.\frac{15}{11}\)

\(=\frac{5}{9}\left(\frac{10}{11}+\frac{14}{11}-\frac{15}{11}\right)\)

\(=\frac{5}{9}.\frac{9}{11}\)

\(=\frac{5}{11}\)

\(\frac{1}{6}\div\left(0,75+\frac{1}{6}\right)-50\%-1^2\)

\(=\frac{1}{6}\div\left(\frac{9}{12}+\frac{2}{12}\right)-\frac{1}{2}-1\)

\(=\frac{1}{6}\div\frac{11}{12}-\frac{1}{2}-\frac{2}{2}\)

\(=\frac{1}{6}.\frac{12}{11}-\frac{3}{2}\)

\(=\frac{2}{11}-\frac{3}{2}\)

\(=\frac{4}{22}-\frac{33}{22}\)

\(=\frac{-29}{22}\)

13/50+9/100+41/100+12/50

=(13/50+12/50)+(9/100+41/100)

=1/2+1/2

=1

11) Ta có:

\(\frac{120-0,5.40.5.0,2.20.0,25-20}{1+5+9+...+33+37}\)

\(=\frac{120-\left(0,5.40\right).\left(5.0,2\right).\left(20.0,25\right)-20}{1+5+9+...+33+37}\)

\(=\frac{120-20.1.5-20}{1+5+9+...+33+37}\)

\(=\frac{120-100-20}{1+5+9+...+33+37}\)

\(=\frac{0}{1+5+9+...+33+37}=0\)

\(\frac{1}{5}\cdot\frac{1}{7}+\frac{4}{5}+\frac{1}{5}\cdot\frac{12}{7}-1-\frac{1}{5}\cdot\frac{6}{7}\)

\(=\frac{1}{5}\cdot\left(\frac{1}{7}+\frac{12}{7}-\frac{6}{7}\right)-\left(1-\frac{4}{5}\right)\)

\(=\frac{1}{5}.1-\frac{1}{5}\)

\(=\frac{1}{5}-\frac{1}{5}=0\)