What is made up of quantities and the operations performed on them

Algebra is made up of quantities and the operations performed on them are addition, subtraction, multiplication and division. 
Algebra is a branch of mathematics. It concerns itself with operations on sets of numbers or other elements. The sets of numbers and elements are represented by symbols. Algebra can be seen as a generalisation of arithmetic.  Letters are substituted for numbers in Algebra. For example, x + 2x will always equal 3x no matter what values the symbol x represents. The algebraic can also include polynomial functions of one or more of the variables.