This chapter explores factors, multiples, prime numbers, co-prime numbers, prime factorisation, and divisibility tests through games, puzzles, and investigations. Students learn how numbers are connected through factors and multiples and how prime numbers act as building blocks of mathematics.
It covers:
• Multiples and common multiples
• Factors and common factors
• Prime and composite numbers
• Sieve of Eratosthenes
• Co-prime numbers
• Prime factorisation
• Divisibility using prime factors
• Divisibility tests for 2, 4, 5, 8, and 10
• Number puzzles and special numbers
• Mathematical games like Idli-Vada and Jump Jackpot
The chapter includes many fun activities, treasure games, thread art, puzzles, and logical investigations to help students understand number relationships creatively.
Overall, this chapter develops logical reasoning, computational thinking, factorisation skills, divisibility understanding, and problem-solving abilities through exploration of numbers and patterns.
🔑 Key Points
• Multiple – Product obtained by multiplying a number with whole numbers.
• Common Multiples – Multiples shared by two or more numbers.
• Least Common Multiple (LCM) – Smallest common multiple of numbers.
• Factor – A number that divides another number exactly.
• Common Factors – Factors shared by two or more numbers.
• Prime Numbers – Numbers having exactly two factors: 1 and itself.
• Composite Numbers – Numbers having more than two factors.
• Number 1 – Neither prime nor composite.
• Even Prime Number – 2 is the only even prime number.
• Sieve of Eratosthenes – Method used to find prime numbers.
• Twin Primes – Prime numbers differing by 2, like 11 and 13.
• Co-prime Numbers – Numbers having only 1 as common factor.
• Prime Factorisation – Writing a number as a product of prime numbers.
• Prime Factors – Prime numbers appearing in prime factorisation.
• Unique Prime Factorisation – Every number has one unique prime factorisation.
• Divisibility – One number divides another exactly without remainder.
• Divisibility by 2 – Number ends in 0, 2, 4, 6, or 8.
• Divisibility by 5 – Number ends in 0 or 5.
• Divisibility by 10 – Number ends in 0.
• Divisibility by 4 – Last two digits form a number divisible by 4.
• Divisibility by 8 – Last three digits form a number divisible by 8.
• Perfect Number – Sum of factors equals twice the number.
• Product of Primes – Composite numbers can be written as products of primes.