Number Theory

Online Activities for 5th & 6th Classes

White Rose Maths: a series of lessons for Year 5 covering Multiples, Factors and Primes, followed by Square and Cube Numbers. For Year 6 there are lessons that include Factors & Common Factors and Multiples, Primes, Square and Cube Numbers.

Matholia: A number of video lessons that include An Introduction to Multiples and An Introduction to Factors

Khan Academy: A series of videos and practice questions exploring Odd & Even Numbers (Grade 3), Factors, Multiples, Prime and Composite Numbers (Grade 4) and Intro to Exponents (Grade 6). You can also register for a free Khan Academy account to record your progress and explore other topics/grades.

Mashup Math - Square Numbers and Square Roots: A video lesson that introduces this concept.

Mathigon Polypad: Use this excellent tool to explore and identify factors of any number, and therefore identify if the number is prime or composite. Can also be used to explore square numbers. Select Tiles > Numbers > Number Tiles and drag out tiles to represent a number. Watch here for a video guide (pupils in 5th and 6th class should start with numbers less than 20 first and then explore bigger numbers when ready)

Odd & Even: A selection of games to identify the odd and even numbers; these might serve useful as revision: Coconut Odd or Even, Fruit Splat Odd or Even, Carroll Diagrams Odd and Even.

Maths Frame - Errors on a Venn Diagram: Identify the numbers which have been placed in the wrong position on the Venn diagram and drag them to their correct place. Choose one or two criteria: to arrange numbers by whether they are odd or even, or multiples of a given number, or prime or square numbers.

Multiples and Factors: multiple choice game, finding the Lowest Common Multiple (LCM) or the Highest Common Factor (HCF). Questions increase in difficulty depending on accuracy.

Maths Frame - Maths Invaders: Shoot the spaceship with the correct answer and dodge the incoming fire. Select play game and then scroll down to select Recognising Multiples, Factors, Prime, Square and Cube Numbers.

Multiplication Blocks: Blast away the correct factors that match the target product

Kakooma: If you choose X then click on the number that is the product of two other numbers (if you choose + then click on the number that is the sum/total of two other numbers)

PhET - Factors: Choose the Factors option to identify the factors of given numbers

Sieve of Eratosthene: Use this interactive sieve to remove multiples, and therefore, identify all the prime numbers from 1-400

Transum - Factor Trees: Complete the Factor Trees to identify the prime factors. Other related activities can be chosen from the Tabs at the top, including Sieve of Eratosthenes, Pick the Primes, HCF and LCM

Hit the Button: Choose the Square Numbers option

Cubes: use this virtual tool to create models of various cubed numbers; click on the settings cog to input your own dimensions

Maths Fishing - Square and Cube Numbers: Practise your multiplication skills. Choose game 18, squared numbers, or 19, cubed numbers. A similar game to this is Archery Arithmetic; again, choose game 18 and/or 19

That Quiz: Use the factors quiz to practice identifying prime and composite numbers, prime factors, HCF and LCM. Use the exponents quiz to practice roots and exponents.

Number Theory and Exponents: two sections of practice games from You can do a number of free quizzes each day without having a subscription. Start with the games just below, or at, your class level.

Math Games: Practice games on Factors and Multiples, Prime and Composite Numbers, Square Roots. Choose your class level.