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Sets Numbers

Maths: Edexcel A Level Pure Maths, topic 1.2.4

What are the Standard Sets of Numbers?

The standard sets of numbers are the sets of numbers most commonly used to investigate expressions, functions and sequences.

What is the set of natural numbers?

What is the set of natural numbers?

  • Natural numbers are the counting numbers like 1, 2, 3, 4, ... and so on.
  • They are also known as whole numbers.
  • The set of natural numbers is written with the symbol ℕ.
  • If a number nn is a natural number, we write n∈n\in ℕ
What is the set of integers?

What is the set of integers?

  • The set of all integers is written with the symbol ℤ.
  • If a number nn is an integer, we write n∈n\in ℤ.
  • The set of all positive integers as the symbol ℤ+.
  • The set of all positive integers including zero as the symbol ℤ0+{}^{+}_{0}.
What is the set of rational numbers?

What is the set of rational numbers?

  • The set of all rational numbers is written with the symbol ℚ.
  • If a number nn is a rational number, we write n∈n\in ℚ.
  • We can also define this set using a rule:
  • ℚ = { pq:p∈ \frac{p}{q}:p\in\,ℤ ,q∈ ,q\in\,ℤ+}
What is the set of real numbers?

What is the set of real numbers?

  • The set of real numbers is written with the symbol ℝ.
  • If a number nn is a real number, we write n∈n\in ℝ.

Test yourself on Sets Numbers

  • Which symbol is used to represent the numbers 1, 2, 3, 4, and so on?

  • A set X is defined as:
    X = { pq:p∈ \frac{p}{q}:p\in\,ℤ ,q∈ ,q\in\,ℤ+}
    What is the name of this set?

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