a: =10/12-7/12=3/12=1/4
b: =2x5/4=10/4=5/2
c: =5/7+3/14=13/14
d: =2/15x3/2=1/5
a) \(\dfrac{5}{6}-\dfrac{7}{12}\)
\(=\dfrac{10}{12}-\dfrac{7}{12}\)
\(=\dfrac{1}{4}\)
b) \(2:\dfrac{4}{5}\)
\(=2\cdot\dfrac{5}{4}\)
\(=\dfrac{5}{2}\)
c) \(\dfrac{5}{7}+\dfrac{3}{7}\cdot\dfrac{1}{2}\)
\(=\dfrac{5}{7}+\dfrac{6}{14}\cdot\dfrac{7}{14}\)
\(=\dfrac{5}{7}+\dfrac{3}{14}\)
\(=\dfrac{10}{14}+\dfrac{3}{14}\)
\(=\dfrac{13}{14}\)
d) \(\left(\dfrac{1}{3}-\dfrac{1}{5}\right):\dfrac{2}{3}\)
\(=\left(\dfrac{5}{15}-\dfrac{3}{15}\right):\dfrac{2}{3}\)
\(=\dfrac{2}{15}\cdot\dfrac{3}{2}\)
\(=\dfrac{1}{5}\)
`a)5/6 - 7/12= 10/12-7/12=3/12=1/4`
`b) 2 : 4/5= 2 xx 5/4= 10/4=5/2`
`c) 5/7 + 3/7 xx 1/2 = 5/7 + 3/14= 10/14 + 3/14=13/14`
`d) ( 1/3 - 1/5 ) : 2/3 =( 5/15 - 3/15) : 2/3= 2/15 xx 3/2= 6/30= 1/5`