\(A=21\frac{4}{11}-\left(1\frac{3}{5}+7\frac{4}{11}\right)\)

\(A=\frac{235}{11}-\left(\frac{8}{5}+\frac{81}{11}\right)\)

\(A=\left(\frac{235}{11}-\frac{81}{11}\right)+\frac{8}{5}\)

\(A=\frac{154}{11}+\frac{8}{5}\)

\(\Rightarrow A=\frac{78}{5}\)

\(B=\left(7\frac{8}{9}+2\frac{3}{13}\right)-\left(4\frac{8}{9}-7\frac{10}{13}\right)\)

\(B=\left(\frac{71}{9}+\frac{29}{13}\right)-\left(\frac{44}{9}-\frac{101}{13}\right)\)

\(B=\left(\frac{71}{9}-\frac{44}{9}\right)+\left(\frac{29}{13}-\frac{101}{13}\right)\)

\(B=\frac{27}{9}+\frac{-72}{13}\)

\(B=3+\frac{-72}{13}\)

\(\Rightarrow B=\frac{-33}{13}\)

P/s: Hoq chắc :v

a) = -3/7 . 5/11 + -3/7 . 6/11 + 9/7

   = -3/7. ( 5/11 + 6/11 ) + 9/7

  = -3/7. 1 + 9/7

  = -3/7 + 9/7

  = 6/7

b) = 4/13 + 9/13 + -11/5 + 6/5 - 3/4

    = 13/13 + -5/5 - 3/4

    = 1 + (-1) - 3/4

    = 0 - 3/4

    = -3/4

c) = -19/17. 4/7 + 19/17. -3/7 + 19/17

    = 19/17. -4/7 + 19/17. -3/7 + 19/17.1

    = 19/17.( -4/7 + -3/7 + 19/17

    = 19/17. -7/7 + 19/17

    = 19/17. (-1) + 19/17

    = -19/17 + 19/17

    = 0

tk mk nha,thanks

a)\(\frac{2}{5}+\left(\frac{3}{11}+\frac{-2}{5}\right)\)

\(=\frac{2}{5}+\frac{3}{11}+\frac{-2}{5}\)

\(=\left(\frac{2}{5}+\frac{-2}{5}\right)+\frac{3}{11}\)

\(=0+\frac{3}{11}\)

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

b)\(\frac{-5}{7}.\frac{4}{13}+\frac{-5}{7}.\frac{9}{13}+\frac{-2}{7}\)

\(=\frac{-5}{7}.\left(\frac{4}{13}+\frac{9}{13}\right)+\frac{-2}{7}\)

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

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

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

Mình có lược bỏ một số bước tính nha.

CHÚC BẠN HỌC GIỎI!

a) \(\frac{2}{5}+\left(\frac{3}{11}+\frac{-2}{5}\right)\)

\(=\frac{2}{5}+\frac{3}{11}+\frac{-2}{5}\)

\(=\left(\frac{2}{5}+\frac{-2}{5}\right)+\frac{3}{11}\)

\(=0+\frac{3}{11}\)

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

b) \(\frac{-5}{7}.\frac{4}{13}+\frac{-5}{7}.\frac{9}{13}+\frac{-2}{7}\)

\(=\frac{-5}{7}\left(\frac{4}{13}+\frac{9}{13}\right)+\frac{-2}{7}\)

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

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

\(=-1\)

\(\left(\frac{3}{4}-\frac{13}{11}+\frac{7}{5}\right)-\left(3-\frac{1}{2}-\frac{35}{11}\right)+\left(\frac{11}{4}-\frac{2}{5}\right)\)

= \(\frac{3}{4}-\frac{13}{11}+\frac{7}{5}-3+\frac{1}{2}+\frac{35}{11}+\frac{11}{4}-\frac{2}{5}\)

= \(\left(\frac{3}{4}+\frac{11}{4}+\frac{1}{2}\right)\left(-\frac{13}{11}+\frac{35}{11}\right)+\left(\frac{7}{5}-\frac{2}{5}\right)-3\)

= \(8+2+1-3\)

= \(8\)

#)Giải :

\(\left(\frac{3}{4}-\frac{13}{11}+\frac{7}{5}\right)-\left(3-\frac{1}{2}-\frac{35}{11}\right)+\left(\frac{11}{4}-\frac{2}{5}\right)\)

\(=\frac{3}{4}-\frac{13}{11}+\frac{7}{5}-3+\frac{1}{2}+\frac{35}{11}+\frac{11}{4}-\frac{2}{5}\)

\(=\left(\frac{3}{4}+\frac{11}{4}\right)+\left(-\frac{13}{11}+\frac{35}{11}\right)+\left(\frac{7}{5}-\frac{2}{5}\right)-3+\frac{1}{2}\)

\(=\frac{7}{2}+2+1-3+\frac{1}{2}\)

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

\(=4\)

34 −35 +37 +311 134 −135 +137 +1311

 \(=\frac{3.\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{11}\right)}{13.\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{11}\right)}\)

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

Tính nhanh :

a) 

\(\left(2+\frac{-7}{13}\right)+\frac{-6}{13}\)

= \(2+\left(\frac{-7}{13}+\frac{-6}{13}\right)\)

= \(2+\frac{-13}{13}=2+\left(-1\right)\)

= 1

tk mk nha

chắc chắn đúng luôn ấy

mk đang âm rất nhiều này ! huhuhu giúp nha  

a)=1

b)=\(-\frac{1}{3}\)

c)=\(\frac{9}{29}\)

A =

B =

C =

C =

C = (4.-12)/(13.17) +

C =

C =

C = 96/221

D = -1/12 - ( 2

D = -1/12 - ( 4

D = -1/12 - (-1

D = -1/12 + 1

-3/36 + 2

D = -1/36

):5/11

E = ):5/11

E = 0:5/11

E = 0

giúp em với : Akai Haruma