The quantities may be equal (=) or equivalence (≡) or equal by definition (≜) or approximately equal (≈)
inequality
it is called an inequality
Equations .
It is any equation which is not an identity.
The relations between quantities are stated by multiplicative relationship between the quantities.
an equation that expresses a relationship between two or more quantities
A proportion is generally multiplicative relationship between two measures of a quantity. An equation is a mathematical statement that relates two quantities. The quantities may contain a number of expressions, with each expression comprising a number of numerical constants, variables and functions.
A ratio shows the relationship between two quantities.Formula
The two quantities are porportional.
It is a ratio
Function
It is a non-linear or non-existent relationship between the two quantities.