Sec 1 Math Chapter 1

What is a prime number?

A prime number is a whole number that has exactly 2 factors, 1 and itself.

Why is 1 not a prime number?

1 is not a prime number as it only has 1 factor while a prime number has exactly 2 factors.

What is prime factorization?

Prime factorization is the process of breaking down a number until only prime numbers is present.

What is HCF(Highest Common Factor)?

HCF is the biggest factors shared by the numbers.

How to find HCF using prime factorization?

Take the shared primes with the smallest power*. ( The smaller sized number above the bigger sized number)

What is LCM(Lowest Common Multiple)?

It is the smallest positive multiple shared by the numbers.

How do you find LCM using prime factorization?

Take all the prime numbers with the biggest power.

Find the HCF and LCM of 12 and 18.

12 divided by 3 equals to 4 4 divided by 2 equals 2 so 12 = 2² × 3

18 divided by 3 equals 6 6 divided by 3 equals 2 so 18 = 2 × 3²

HCF = 2 × 3 = 6

LCM = 2² × 3² = 36