a)
`6:5/2-3/10`
`=6xx2/5-3/10`
`=12/5-3/10`
`=24/10-3/10`
`=21/10`
b)
`4/6:4/3+5:4/3`
`=2/3xx3/4+5xx3/4`
`=3/4xx(2/3+5)`
`=3/4xx(2/3+15/3)`
`=3/4xx17/3`
`=17/4`
\(a,6:\dfrac{5}{2}-\dfrac{3}{10}\\ =\dfrac{6}{1}:\dfrac{5}{2}-\dfrac{3}{10}\\ =\dfrac{6}{1}\times\dfrac{5}{2}-\dfrac{3}{10}\\ =\dfrac{12}{5}-\dfrac{3}{10}\\ =\dfrac{12\times2}{5\times2}-\dfrac{3}{10}\\ =\dfrac{24}{10}-\dfrac{3}{10}\\ =\dfrac{21}{10}\)
\(b,\dfrac{4}{6}:\dfrac{4}{3}+5:\dfrac{4}{3}\\ =\dfrac{4}{6}:\dfrac{4}{3}+\dfrac{5}{1}:\dfrac{4}{3}\\ =\dfrac{4}{3}:\left(\dfrac{4}{6}+\dfrac{5}{1}\right)\\ =\dfrac{4}{3}:\left(\dfrac{4}{6}+\dfrac{5\times6}{1\times6}\right)\\ =\dfrac{4}{3}:\left(\dfrac{4}{6}+\dfrac{30}{6}\right)\\ =\dfrac{4}{3}:\dfrac{34}{6}\\ =\dfrac{4}{3}:\dfrac{17}{3}\\ =\dfrac{4}{3}\times\dfrac{3}{17}\\=\dfrac{12}{51} \\ =\dfrac{4}{17}.\)
\(a,6:\dfrac{5}{2}-\dfrac{3}{10}=6\times\dfrac{5}{2}-\dfrac{3}{10}=\dfrac{12}{5}-\dfrac{3}{10}=\dfrac{24}{10}-\dfrac{3}{10}=\dfrac{21}{10}\)
\(b,\dfrac{4}{6}:\dfrac{4}{3}+5:\dfrac{4}{3}=\dfrac{4}{6}\times\dfrac{3}{4}+5\times\dfrac{3}{4}=\dfrac{2}{4}+\dfrac{15}{4}=\dfrac{17}{4}\)
