Use Of Variables in Common Rules

Use of Variables in Common Rules


Rules from geometry

Algebraic expressions can be used in formulating perimeter of figures.
Example: Let L be the length of one side then, the perimeter of:

An equilateral triangle = 3L.

A square = 4L.

A regular pentagon = 5L.

Rules from Arithmetic

  1. Commutativity of Addition
    Let a and b be two variables, which can take any numerical value.
    Then, a + b = b + a
  2. Commutativity of Multiplication
    Let a and b be two variables.
    Then, a × b = b × a
  3. Distributivity of multiplication over addition
    Let a, b and c be three variables.
    Then a × (b + c) = a × b + a × c
  4. Associativity of addition
    Let a, b and c be three variables.
    Then, (a + b) + c = a + (b + c).
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