~Maths and Logic fundamentals (Number Categories and Set Notations)~

The first lesson of Maths and Logic fundamentals introduced 4 number categories;

Natural - 1, 2, 3 (Whole numbers), Integer - -1, -2, -3, 0, 1, 2, 3 (Whole numbers and their negatives) Rational - 1/2 = 0.5, 1/3 = 0.333 (Ratios of integers), Real - π, e (Every value on a non gapped number line including Pi and mathematical constant). Set: A set is a collection of distinct objects which are considered as objects in their own right.

Cardinality: If there are three objects within a set, that set then has a cardinality of 3.

{2, 4, 6} - Has a cardinality of three.

{6, 4, 2} - Also has a cardinality of three and the same objects (these do NOT have to be in any sort of order as the last set). Because of this they're equal sets.

{x, y, z} - This is a finite set. {x, y, z,...} - The ellipses states that this is an infinite set. Set notations; ∈ - Included within/an element of. ∉ - Not included within/not an element of.

⊆ - A subset of. ⊄ - Not a subset of. Ø - Null/empty.

EXAMPLES When A = {x, y, z}, B = {x, y} ⊆ A (Set B is a subset/part of set A). B = {a ,b} ⊄ A (Set B is not a subset/part of A).

When A = { },

A is Ø (Because there is nothing present.)