The SI units for mass is kilograms. Weight is a force with units Newtons.
In the strengthening exercise in Maths, the " volume of the water" was rejected.
Volume=Όγκος (liters), Mass=Μάζα (kilos). They are different things, that's why volume is not accepted. :/
Doesn't "mass" have the same meaning as "weight"?
mass is how much materia a body contains
weight is the gravitational force on a body
on the moon your weight is less than on earth but your mass is the same
the water mass