a)=33/35
b)=47/8
Bài làm
a) \(\left(\frac{1}{2}+\frac{4}{7}\right)-\left(\frac{3}{7}-\frac{3}{10}\right)\)
\(=\frac{1}{2}+\frac{4}{7}-\frac{3}{7}+\frac{3}{10}\)
\(=\frac{35}{70}+\frac{40}{70}-\frac{30}{70}+\frac{21}{70}\)
\(=\frac{66}{70}\)
\(=\frac{33}{35}\)
b) \(\left(\frac{3}{5}x\frac{4}{5}x\frac{5}{9}\right):\left(\frac{7}{9}-\frac{3}{5}\right)\)
\(=\left(\frac{1}{5}x\frac{4}{3}\right):\left(\frac{35}{45}-\frac{27}{45}\right)\)
\(=\frac{4}{15}:\frac{8}{45}\)
\(=\frac{4}{15}.\frac{45}{8}\)
\(=\frac{1}{1}.\frac{3}{2}\)
\(=\frac{3}{2}\)
a) ( 1/2 + 4/7 ) - ( 3/7 -3/10 )
= 15/14 - 9/70
= 66/70
b) ( 3/5 + 4/5 x 5/9 ) : ( 7/9 -3/5 )
= 5/9 : 8/45
= 225/72
a, \(\left(\frac{1}{2}+\frac{4}{7}\right)-\left(\frac{3}{7}-\frac{3}{10}\right)\)
\(=\frac{1}{2}+\frac{4}{7}-\frac{3}{7}+\frac{3}{10}\)
\(=\frac{35}{70}+\frac{40}{70}-\frac{30}{70}+\frac{21}{70}\)
\(=\frac{66}{70}\)
\(=\frac{33}{35}\)
b, \(\left(\frac{3}{5}+\frac{4}{5}\times\frac{5}{9}\right)\div\left(\frac{7}{9}-\frac{3}{5}\right)\)
\(=\left(\frac{3}{5}+\frac{4}{9}\right)\div\frac{8}{45}\)
\(=\frac{47}{45}\times\frac{45}{8}\)
\(=\frac{47}{8}\)
