1.[tex](-2\frac{1}{2} ):(\frac{1}{4} )=\frac{-5}{2} *\frac{4}{1} =\frac{-20}{2} =-10[/tex]
2.[tex]3:(-2\frac{1}{4} )=3:-\frac{9}{4} =3* -\frac{4}{9} =-\frac{4}{3}[/tex]
3.[tex]3\frac{2}{5} *\frac{-2}{4} =-\frac{34}{20} =-\frac{17}{10}[/tex]
4.[tex]-2.7*(-3*\frac{1}{2})=-\frac{27}{10} *-\frac{3}{2} =\frac{81}{10}[/tex]