Tuition Singapore Secondary Math Tuition -Prime Numbers, Prime Factorisation and Index Notation

Note : 0 and 1 are neither prime nor composite numbers

1. A prime number is a whole number greater than 1 that has exactly two different

factors, 1 and itself.

E.g. 5 = 1 x 5

Since 5 has no other whole number factors other than 1 and itself, it is a prime number.

2. The numbers 2, 3, 5, 7, 11, 13, 17, … are prime numbers.
3. A composite number is a whole number greater than 1 that has more than 2 different

factors.

6 is a composite number.

4. The numbers 4, 6, 8, 9, 10, 12, 14, 15, 16, … are composite numbers. In other words,

all whole numbers greater than 1 that are not prime numbers are composite numbers.

     5. Prime factors are factors of a number that are also prime.

E.g. The factors of 18 are 1, 2, 3, 6, 9 and 18. The prime factors of 18 are 2 and 3.

     6. The process of expressing a composite number as the product of prime factors is called prime factorisation.

     7. We can use either the factor tree or repeated division to express a composite number as a product of its prime factors.

Please contact Angie @ 96790467 or Mr Ong @ 98639633 if you need tuition on Lower Secondary Math