= -97/1176 ^{lớp 4 học số âm à???}

-97/1176 

-97/1176 

  1/2x1/3+1/3x1/4+1/4x1/5+1/5x1/6+1/6x1/7+1/7x1/8+1/8x1/9

=7/18

\(\left(\dfrac{6}{7}+\dfrac{3}{14}\right):\dfrac{3}{7}\times\dfrac{1}{70}\)

\(=\left(\dfrac{12}{14}+\dfrac{3}{14}\right):\dfrac{3}{7}\times\dfrac{1}{70}\)

\(=\dfrac{15}{14}:\dfrac{3}{7}\times\dfrac{1}{70}\)

\(=\dfrac{15}{14}\times\dfrac{7}{3}\times\dfrac{1}{70}\)

\(=\dfrac{15\times7\times1}{14\times3\times70}\)

\(=\dfrac{105}{2940}=\dfrac{1}{28}\)

\(\left(\dfrac{6}{7}+\dfrac{3}{14}\right):\dfrac{3}{7}\times\dfrac{1}{70}\)

\(=\left(\dfrac{12}{14}+\dfrac{3}{14}\right)\times\dfrac{7}{3}\times\dfrac{1}{70}\)

\(=\dfrac{15}{14}\times\dfrac{1}{30}\)

\(=\dfrac{1}{28}\)

\(6\dfrac{1}{7}\times1\dfrac{6}{7}\)

\(=\dfrac{43}{7}\times\dfrac{13}{7}\)

\(=\dfrac{559}{49}\)

#Toru

\(6\dfrac{1}{7}\times1\dfrac{6}{7}=\dfrac{43}{7}\times\dfrac{13}{7}=\dfrac{559}{49}\)

-6/35

1/5x (4/7- 3/7- 1)=1/5x -6/7= -6/35

\(-\dfrac{6}{35}\)

\(\dfrac{1}{5}\times\dfrac{4}{7}+\dfrac{3}{7}\times\dfrac{1}{5}-\dfrac{1}{5}\)

\(=\dfrac{4}{35}+\dfrac{3}{35}-\dfrac{1}{5}\)

\(=\dfrac{7}{35}-\dfrac{1}{5}\)

\(=\dfrac{1}{5}-\dfrac{1}{5}\)

\(=0\)

0

\(=\dfrac{3}{7}\times\left(\dfrac{1}{5}+\dfrac{2}{3}-\dfrac{1}{8}\right)\\ =\dfrac{3}{7}\times\left(\dfrac{24}{5\times24}+\dfrac{2\times40}{3\times40}-\dfrac{15}{8\times15}\right)\\ =\dfrac{3}{7}\times\left(\dfrac{24+80-15}{120}\right)\\ =\dfrac{3}{7}\times\dfrac{89}{120}\\ =\dfrac{89}{280}\)

\(\dfrac{3}{7}\times\dfrac{1}{5}+\dfrac{2}{3}\times\dfrac{3}{7}-\dfrac{3}{7}\times\dfrac{1}{8}\)
\(=\dfrac{3}{7}\times\left(\dfrac{1}{5}+\dfrac{3}{7}-\dfrac{1}{8}\right)\)
\(=\dfrac{3}{7}\times\dfrac{56+120-35}{280}\)
\(=\dfrac{3}{7}\times\dfrac{141}{280}\)
\(=\dfrac{423}{1960}\)

tíc cho mình nha

2/3 - 7/24 = 3/8 

\(\frac{2}{3}-\left(\frac{1}{6}+\frac{1}{8}\right)\)=\(\frac{16}{24}-\left(\frac{4}{24}+\frac{3}{24}\right)\)=\(\frac{16}{24}-\frac{7}{24}=\frac{9}{24}=\frac{3}{8}\)