[tex]a)\\a+2.4=7.8\\a=7.8-2.4\\a=5.4\\\\b)\\b-\dfrac{1}{4} =3\dfrac{1}{2} \\b-0.25=3.5\\b=3.5+0.25\\b=3.75=3\dfrac{3}{4} \\\\c)\\\dfrac{1}{3} s=\dfrac{1}{5} \\s=\dfrac{1}{5}\div\dfrac{1}{3}\\s=\dfrac{1}{5}\times3\\s=\dfrac{3}{5} \\\\d)\\3x=27\\x=27\div3\\x=9\\\\e)\\\dfrac{t}{4} =16|\times4\\t=64\\\\f)\\\dfrac{w}{7} =0.3|\times7\\w=2.1[/tex]
Check:
[tex]a)\\5.4+2.4=7.8\\correct\\\\b)\\3\dfrac{3}{4}-\dfrac{1}{4} -3\dfrac{2}{4}=3\dfrac{1}{2}\\correct\\\\c)\\\dfrac{1}{3} \times \dfrac{3}5=\dfrac1{5}\\correct\\\\d)\\3\times9=27\\correct\\\\e)\\\dfrac{64}{4} =16\\corect\\\\f)\\\dfrac{2.1}{7} =0.3\\correct[/tex]
