\(\left(\frac{3}{4}+\frac{2}{11}-\frac{8}{13}\right)+\left(\frac{1}{4}-\frac{5}{13}\right)\)

\(=\frac{3}{4}+\frac{2}{11}-\frac{8}{13}+\frac{1}{4}-\frac{5}{13}\)

\(=\left(\frac{3}{4}+\frac{1}{4}\right)+\frac{2}{11}-\left(\frac{8}{13}+\frac{5}{13}\right)\)

\(=1+\frac{2}{11}-1\)

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

\(\left(\frac{9}{53}+\frac{21}{31}\right)+\left(\frac{44}{53}-\frac{16}{7}\right)+\frac{10}{31}\)

\(=\frac{9}{53}+\frac{21}{31}+\frac{44}{53}-\frac{16}{7}+\frac{10}{31}\)

\(=\left(\frac{9}{53}+\frac{44}{53}\right)+\left(\frac{21}{31}+\frac{10}{31}\right)-\frac{16}{7}\)

\(=1+1-\frac{16}{7}\)

\(=2-\frac{16}{7}\)

\(=\frac{14}{7}-\frac{16}{7}\)

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

=7/30

4/3 + -11/31 + 3/10 - 20/31 - 2/5 = 7/30

\(\dfrac{4}{3}+\dfrac{-11}{31}+\dfrac{3}{10}-\dfrac{20}{31}-\dfrac{2}{5}\)

\(=\dfrac{4}{3}+\left(\dfrac{-11}{31}+\dfrac{-20}{31}\right)+\left(\dfrac{3}{10}-\dfrac{2}{5}\right)\)

\(=\dfrac{4}{3}+-1+\dfrac{-1}{10}\)

\(=\dfrac{1}{3}+\dfrac{-1}{10}\)

\(=\dfrac{7}{30}\)

Chúc bạn học tốt

= 91/93 + -107/310 - 2/5

= 19/30 - 2/5

= 7/30

1,35326087

-2/3

0

-6/29/44

-9

nha bạn

Bài 1: Ta chỉ cần bỏ ngoặc rồi cộng hai phân số để ra kết quả là số tự nhiên là xong

Bài 2:

A = \(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+............+\frac{1}{2003.2004}\)

A = \(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-.............-\frac{1}{2003}+\frac{1}{2003}-\frac{1}{2004}\)

A = \(1-\frac{1}{2004}\)

A = \(\frac{2004}{2004}-\frac{1}{2004}=\frac{2003}{2004}\)

Mk làm mẫu 1 bài nha 

Bài 1 :

a, = (1/4+3/4) - (5/13+8/13)+2/11

    = 1 - 1 + 2/11

    = 2/11

Tk mk nha

\(A=\dfrac{5}{11}.\dfrac{5}{7}+\dfrac{5}{11}.\dfrac{2}{7}+\dfrac{6}{11}=\dfrac{5}{11}\left(\dfrac{5}{7}+\dfrac{2}{7}\right)+\dfrac{6}{11}=\dfrac{5}{11}.1+\dfrac{6}{11}=\dfrac{5}{11}+\dfrac{6}{11}=\dfrac{11}{11}=1\)

\(B=\dfrac{3}{13}.\dfrac{6}{11}+\dfrac{3}{13}.\dfrac{9}{11}-\dfrac{3}{13}.\dfrac{4}{11}=\dfrac{3}{13}\left(\dfrac{6}{11}+\dfrac{9}{11}-\dfrac{4}{11}\right)=\dfrac{3}{13}.1=\dfrac{3}{13}\)

\(C=\left(\dfrac{12}{16}-\dfrac{31}{22}+\dfrac{14}{91}\right)\left(\dfrac{1}{2}-\dfrac{1}{3}-\dfrac{1}{6}\right)=\left(\dfrac{12}{16}-\dfrac{31}{22}+\dfrac{14}{91}\right)\left(\dfrac{3}{6}-\dfrac{2}{6}-\dfrac{1}{6}\right)=\left(\dfrac{12}{16}-\dfrac{31}{22}+\dfrac{14}{91}\right).0=0\)

a: \(5\cdot11\cdot18+9\cdot31\cdot10+4\cdot29\cdot45\)

\(=11\cdot\left(5\cdot18\right)+31\cdot\left(9\cdot10\right)+29\cdot2\cdot\left(2\cdot45\right)\)

\(=90\left(11+31+29\cdot2\right)\)

\(=90\cdot100=9000\)

b: \(37\cdot39+78\cdot14+13\cdot85+52\cdot55\)

\(=37\cdot39+39\cdot2\cdot14+13\cdot85+13\cdot4\cdot55\)

\(=39\left(37+2\cdot14\right)+13\cdot\left(85+4\cdot55\right)\)

\(=39\cdot65+13\cdot305\)

\(=13\left(65\cdot3+305\right)=13\cdot500=6500\)

a)

5.11.18+9.31.10+4.29.455.11.18+9.31.10+4.29.45

=90.11+90.31+2.29.90=90.11+90.31+2.29.90

=90.(11+31+2.29)=90.(11+31+2.29)

=90.100=9000

b)

37.39+78.14+13.85+52.5537.39+78.14+13.85+52.55

=37.39+39.2.14+13.5.17+13.4.5.11=37.39+39.2.14+13.5.17+13.4.5.11

=39.(37+2.14)+65.17+65.44=39.(37+2.14)+65.17+65.44

=39.65+65.(17+44)=39.65+65.(17+44)

=39.65+65.61=39.65+65.61

=65.(39+61)=65.(39+61)

=65.100=6500

1) \(\dfrac{1}{2}+\dfrac{13}{19}-\dfrac{4}{9}+\dfrac{6}{19}+\dfrac{5}{18}\)

\(=\dfrac{1}{2}+\left(\dfrac{13}{19}+\dfrac{6}{19}\right)-\dfrac{4}{9}+\dfrac{5}{18}\)

\(=\dfrac{3}{2}-\dfrac{4}{9}+\dfrac{5}{18}\)

\(=\dfrac{19}{18}+\dfrac{5}{18}\)

\(=\dfrac{24}{18}\)

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

2) \(\dfrac{-20}{23}+\dfrac{2}{3}-\dfrac{3}{23}+\dfrac{2}{5}+\dfrac{7}{15}\)

\(=\left(-\dfrac{20}{23}-\dfrac{3}{23}\right)+\dfrac{2}{3}+\dfrac{2}{5}+\dfrac{7}{15}\)

\(=-1+\dfrac{2}{3}+\dfrac{2}{5}+\dfrac{7}{15}\)

\(=-\dfrac{1}{3}+\dfrac{2}{5}+\dfrac{7}{15}\)

\(=\dfrac{1}{15}+\dfrac{7}{15}\)

\(=\dfrac{8}{15}\)

3) \(\dfrac{4}{3}+\dfrac{-11}{31}+\dfrac{3}{10}-\dfrac{20}{31}-\dfrac{2}{5}\)

\(=\left(\dfrac{-11}{31}-\dfrac{20}{31}\right)+\dfrac{4}{3}+\dfrac{3}{10}-\dfrac{2}{5}\)

\(=-1+\dfrac{4}{3}+\dfrac{3}{10}-\dfrac{2}{5}\)

\(=\dfrac{1}{3}+\dfrac{3}{10}-\dfrac{2}{5}\)

\(=\dfrac{1}{3}-\dfrac{1}{10}\)

\(=\dfrac{7}{30}\)

4) \(\dfrac{5}{7}.\dfrac{5}{11}+\dfrac{5}{7}.\dfrac{2}{11}-\dfrac{5}{7}.\dfrac{14}{11}\)

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

\(=\dfrac{5}{7}.-\dfrac{7}{11}\)

\(=-\dfrac{35}{77}\)

\(=-\dfrac{5}{11}\)

4/5.31/2-4/5.46/3

=4/5.(31/2-46/3)

=4/5.(93/6-92/6)

=4/5.1/6

=4/30=2/15

k cho tui na

\(\frac{4}{5}\cdot\frac{31}{2}-\frac{4}{5}\cdot\frac{46}{3}\)

\(=\frac{4}{5}\cdot\left(\frac{31}{2}-\frac{46}{3}\right)\)

\(=\frac{4}{5}\cdot\left(\frac{93}{6}-\frac{92}{6}\right)\)

\(=\frac{4}{5}\cdot\frac{1}{6}\)

\(=\frac{4.1}{5\cdot6}=\frac{4}{30}=\frac{4:2}{30:2}=\frac{2}{15}\)

A)  7/38 x 9/11 +7/38 x 4/11 -7/38 x 2/11

=7/38.(9/11+4/11-2/11)

=7/38

B) 5/31 x 21/25 + 5/31 x -7/10 - 5/31 x 9/20

=5/31.(21/25-7/10-9/20)

=5/31.(-31/100)

=-1/20