Numbers

• Show and explain the natural number set


  Any positive whole number including 0

  • ℕ = {0,1,2,3,...}
• Show and explain the integer set


  Any positive or negative whole number including 0

  • ℤ = {..., -2, -1 , 0 , 1 , 2 ,...}
• Show and explain the rational number set


  Any number that can be represented as a fraction

  • ℚ = {-3/4, 5/1, 8/8, 0, ...}
• Show and explain the irrational number set


  Any number that cannot be expressed as a fraction

  • pi, root2
• Show and explain the real number set


  ANY positive or negative number

  • ℝ = {-3/4, -1, 0, pi, 5/5,...}
• What is an ordinal


  A number that is used to identify relative position

  eg 1st, 2nd 3rd...
• What are cardinal numbers


  Numbers that are used to identify the size of something

  eg 20 bananas
• What is a well-ordered list

  A group of related values with a defined order
• What number set is used for counting and why


  Natural numbers

  Because we only count using +ve whole numbers
• What number set is used for measurement and why


  Real numbers

  Because we measure using +ve or -ve numbers that may require a fractional part