First, some definition:
d=density of solution, g/ml
C%= percent concentration of solution, means the mass (g) of solute per 100g solution.
Cm=molarity of solution, mole/L.
M: molecule mass of solute.
If the Cm is provided, mean Cm moles of solute in 1L(1000ml) solution, the we calculate:
-Mass of solute=Cm*M, set m1
-Mass of solution= d*V=d*1000, set it m0
Similarily, you can calculate Cm from C% from the equation above, pay attention to the unit. The important thing is that you understand the meaning of each terms.