LCHL Maths – Number Theory

Leaving Cert Higher Level Maths LCHL Maths – Number Theory

LCHL Number Theory

The LCHL Number Theory strand — types of numbers, prime factorisation, and the famous proof that √2 is irrational. Work through every lesson in order, learn the key facts, and check your answers against fully worked solutions.

Your progress through this topic0 of 5 lessons

Lessons in this topic

All 5 lessons, in order — each one ticks off as you open it.

1Types of numbers2Prime Factorisation3Number Theory 3 Proof by contradiction: Prove root 2 is irrational★ Learn off4Number Theory 4 Construct √2★ Learn off5Construct √3★ Learn off

Key ideas in this topic

★ Must learn
Natural numbers (ℕ)
Natural numbers (ℕ)Number Theory 1
★ Must learn
Integers (ℤ)
Integers (ℤ)Number Theory 1
★ Must learn
Rational numbers (ℚ)
Rational numbers (ℚ)Number Theory 1
★ Must learn
Irrational numbers
Irrational numbersNumber Theory 1
★ Must learn
Real numbers (ℝ)
Real numbers (ℝ)Number Theory 1
📖 In the log tables
The number sets
The number setsNumber Theory 1
📖 In the log tables
Prime factorisation
Prime factorisationNumber Theory 2
📖 In the log tables
√2 is irrational
√2 is irrationalNumber Theory 3

The two constructions

★ Must learn
Construct √2
Construct √2Number Theory 4
★ Must learn
Construct √3
Construct √3Number Theory 5

Check it against the exam

Jump straight to the fully worked solution for that paper.

2023 Paper 1 Q3 →2023 Paper 1 Q9 →2022 Paper 1 Q1 →2022 Paper 1 Q2 →2022 Paper 2 Q6 →

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