BÀI 1

a,  \(5\times\frac{-7}{10}=\frac{-35}{10}=\frac{-7}{2}\)

b,  \(\frac{4}{5}\times\frac{-7}{10}=\frac{-28}{50}=\frac{-14}{25}\)

c,  \(\frac{4}{9}+\frac{4}{3}\times\frac{16}{4}=\frac{4}{9}+\frac{16}{3}=\frac{52}{9}\)

d,  \(\frac{11}{22}-\frac{3}{9}\times\frac{14}{21}=\frac{11}{22}-\frac{2}{9}=\frac{55}{198}=\frac{5}{18}\)  

BÀI 2

\(A=\frac{6}{13}\times\frac{5}{7}+\frac{6}{13}\times\frac{2}{7}+\frac{17}{13}\)

\(A=\frac{30}{91}+\frac{12}{91}+\frac{17}{13}\)

\(A=\frac{30}{91}+\frac{12}{91}+\frac{119}{91}\)

\(A=\frac{161}{91}=\frac{23}{13}\)

\(B=\frac{11}{15}\times\frac{4}{11}+\frac{11}{15}\times\frac{5}{11}+\frac{11}{15}\times\frac{2}{11}\)

\(B=\frac{4}{15}+\frac{1}{3}+\frac{2}{15}\)

\(B=\frac{11}{15}\)

\(C=\left(\frac{19}{64}-\frac{33}{22}+\frac{24}{51}\right)\times\left(\frac{1}{5}-\frac{1}{15}-\frac{2}{15}\right)\)

\(C=\frac{-797}{1088}\times0\)

\(C=0\)

\(D=\frac{8}{13}\times\frac{7}{12}+\frac{8}{13}\times\frac{5}{12}-\frac{1}{12}\)

\(D=\frac{14}{39}+\frac{10}{39}-\frac{1}{12}\)

\(D=\frac{83}{156}\)

bạn biết câu náy không (24 + 11) . {546 - [14 . (64 - 2^{3}3) : 2]} =

\(\dfrac{-5}{7}-\dfrac{9}{22}+\dfrac{5}{17}-\dfrac{13}{22}\\ =-\dfrac{5}{7}+\dfrac{5}{17}+\left(-\dfrac{9}{22}-\dfrac{13}{22}\right)\\ =-\dfrac{5}{7}+\dfrac{5}{17}-\dfrac{22}{22}\\ =-\dfrac{5}{7}+\dfrac{5}{17}-1\\ =\dfrac{-5\times17+5\times7-119}{119}\\ =\dfrac{-85+35-119}{119}=\dfrac{-169}{119}\)

Bài 1 : Tính bằng cách thuận tiện 

A = 3/13 x 5/7 + 2/13 x 3/7

= 2/13 + 1/13 x 5/7 + 2/13 x 3/7

=  2/13 x 72/91 + 2/13 x 3/7

= 2/13 x ( 72/91 + 3/7 )

= 2/13 x  37/24

= 37/156.

B = 21/22 x 17/8 + 21/8 x 7/22

= 21/22 x 17/8 + 17/8 + 4/8 x 7/22

=  21/22 x 17/8 + 17/8 x 7/44

=  ( 21/22 + 7/44 ) x 21/22

=  31/44 x 21/22

=  651/968.

Chúc bạn học tốt!!!

\(a,\dfrac{2}{13}\times\dfrac{22}{5}\times\dfrac{13}{2}\\ =\left(\dfrac{2}{13}\times\dfrac{13}{2}\right)\times\dfrac{22}{5}\\ =1\times\dfrac{22}{5}=\dfrac{22}{5}\\ b,\dfrac{3}{5}\times\dfrac{6}{7}+\dfrac{6}{7}\times\dfrac{3}{5}\\ =\dfrac{3}{5}\times\left(\dfrac{6}{7}+\dfrac{6}{7}\right)\\ =\dfrac{3}{5}\times\dfrac{12}{7}=\dfrac{36}{35}\)

\(a,=\left(\dfrac{2}{13}\times\dfrac{13}{2}\right)\times\dfrac{22}{5}=\dfrac{22}{5}\\ b,=\dfrac{3}{5}\times\left(\dfrac{6}{7}+\dfrac{6}{7}\right)\\ =\dfrac{3}{5}\times\dfrac{12}{7}\\ =\dfrac{36}{35}\)

B=522+313−12413−211+32

 Đặt \(S=\frac{5}{22}+\frac{3}{13}-\frac{1}{2}\)

=> S= \(\frac{-6}{143}\)

Đặt \(H=\frac{4}{13}-\frac{2}{11}+\frac{3}{2}\)

=> H = \(\frac{465}{286}\)

Khi đó B = \(\frac{\frac{-6}{143}}{\frac{465}{286}}\)=\(\frac{-4}{155}\)

ai có thể chỉ giúp tôi được ko vì tôi cần rất gấp

\(a,\dfrac{-5}{13}+\dfrac{8}{13}=\dfrac{3}{13}\\ b,\dfrac{5}{31}+\dfrac{-22}{31}=\dfrac{-17}{31}\\ c,\dfrac{-13}{43}+\dfrac{-40}{43}=\dfrac{-53}{43}\\ d,\dfrac{-3}{29}-\dfrac{16}{58}=\dfrac{-11}{29}\\ e,\dfrac{8}{40}-\dfrac{-36}{45}=1\\ f,\dfrac{-8}{18}-\dfrac{-15}{27}=\dfrac{1}{9}\\ g,\left(-2\right)+\dfrac{-5}{8}=\dfrac{-21}{8}\)

    42 x 13 - 22 x 5 + 42 x 7 - 15 x 22

= (42 x 13 + 42 x 7) - (22 x 5 + 15 x 22)

= [42 x (13 + 7)] - [22 x (5 + 15)]

= 42 x 20 - 22 x 20

= 20 x (42 - 22)

= 20 x 20 

= 400 

\(42\cdot13-22\cdot5+42\cdot7-15\cdot22\)   

\(=42\cdot\left(13+7\right)-22\cdot\left(5+15\right)\)   

\(=42\cdot20-22\cdot20\)    

\(=20\cdot\left(42-22\right)\)   

\(=20\cdot20\)   

\(=400\)

\(42\cdot13-22\cdot5+42\cdot7-15\cdot22\)

\(=42\cdot\left(13+7\right)-22\cdot\left(15+5\right)\)

\(=42\cdot20-22\cdot20\)

\(=20\cdot\left(42-22\right)\)

\(=20\cdot20\)

\(=400\)