Because its numerical value is the same under all possible systems of units, it is a dimensionless quantity.

For the purposes of the experimenter, different systems that share the same description by dimensionless quantity are equivalent.

Information capacity is a dimensionless quantity, because it refers to a count of binary symbols.

Unlike most physical quantities, particle number is a dimensionless quantity.

However atomic weight is a dimensionless quantity, and cannot take the units of grams per mole.

Effectiveness is dimensionless quantity between 0 and 1.

Being a dimensionless quantity, it has constant numerical value in all systems of units.

For a gas, the activity is simply the fugacity divided by a reference pressure to give a dimensionless quantity.

Rewrite the system of equations in terms of their new dimensionless quantities.

There are infinitely many dimensionless quantities and they are often called numbers.