Learning objective
Ordinal numbers: Be familiar with the concept of ordinal numbers and their use to describe the numerical positions of objects. When objects are placed in order, ordinal numbers are used to tell their position. For example, if we have a well-ordered set S = {‘a’, ‘b’, ‘c’, ‘d’}, then ‘a’ is the 1st object, ‘b’ the 2nd, and so on.
Read the explanation, check the common trap, then practise with flashcards and questions.
At a glance
0
Flashcards
0
Questions
Topic
Number systems
Subtopic
Ordinal numbers
Aqa A Level Computer ScienceFundamentals of data representation
Study support
Understand this objective
Quick explanation
Ordinal numbers: Be familiar with the concept of ordinal numbers and their use to describe the numerical positions of objects. When objects are placed in order, ordinal numbers are used to tell their position. For example, if we have a well-ordered set S = {‘a’, ‘b’, ‘c’, ‘d’}, then ‘a’ is the 1st object, ‘b’ the 2nd, and so on
- This point belongs to Number systems, especially Ordinal numbers.
- You need to be able to ordinal numbers: Be familiar with the concept of ordinal numbers and their use to describe the numerical positions of objects. When objects are placed in order, ordinal numbers are used to tell their position. For example, if we have a well-ordered set S = {‘a’, ‘b’, ‘c’, ‘d’}, then ‘a’ is the 1st object, ‘b’ the 2nd, and so on.
- Use the linked flashcards and practice questions to check recall, then practise applying the idea in an exam-style answer.
Why it matters
This objective helps connect Ordinal numbers to exam-style questions, flashcards, and revision notes for Number systems.
Quick student answer
The objects in the ordered set S = {"red", "blue", "green", "yellow"} are written from left to right. What is the ordinal position of "green"?
Direct answer
The ordinal position of "green" is 3rd.
Key terms
- Ordinal number: A number that describes the numerical position of an object in an ordered arrangement.
- Well-ordered set: A set whose objects have been placed in a definite order, allowing their positions to be described using ordinal numbers.
Common trap
Swapping adjacent positions: Read the set from the beginning and count each object carefully, assigning positions in sequence: 1st, 2nd, 3rd, 4th.
Related questions
Try this as a practice card
Question 1 of 4
Choose an answer, get feedback, then move sideways through the set.
0 of 4 attempted
Flashcard prompts
Flip through the key recall cards
Flashcard 1 of 4
Press Space to flip, arrows to move
Revision tools
Choose how to practise
Flashcards0 linked cards
No objective-specific flashcards are cached for this page. Use the topic hub to revise the surrounding flashcards without triggering a frozen-subject DB fallback.Open topic hub
Practice Questions0 linked questions
No objective-specific practice questions are cached for this page. Use the topic question bank to practise nearby curriculum questions without weakening the egress guard.Open topic questions
Related learning objectives
- Natural numbers: Be familiar with the concept of a natural number and the set ℕ of natural numbers (including zero). ℕ = {0, 1, 2, 3, … }
Natural numbers
- Integer numbers: Be familiar with the concept of an integer and the set ℤ of integers. ℤ = { …, -3, -2, -1, 0, 1, 2, 3, … }
Integer numbers
- Rational numbers: Be familiar with the concept of a rational number and the set ℚ of rational numbers, and that this set includes the integers. ℚ is the set of numbers that can be written as fractions (ratios of integers). Since a number such as 7 can be written as 7/1, all integers are rational numbers.
Rational numbers
- Irrational numbers: Be familiar with the concept of an irrational number. An irrational number is one that cannot be written as a fraction, for example √2.
Irrational numbers
- Real numbers: Be familiar with the concept of a real number and the set ℝ of real numbers, which includes the natural numbers, the rational numbers and the irrational numbers. ℝ is the set of all 'possible real world quantities'.
Real numbers