Numbers can be multiplied to get a product. These numbers are called factors of the product.
Multiples of a number are obtained by multiplying the number by natural numbers.
Prime numbers are those numbers which have just two factors, one and the number itself.
Composite numbers have more than two factors
Two numbers are considered co-prime numbers if they do not have any number other than one as a common factor.
Highest Common Factor or HCF of two numbers is the largest number which is a common factor for these numbers.
Least Common Multiple or LCM of two numbers is the smallest number which is a common multiple for these numbers.
Learn about prime factorisation and common division methods for finding HCF and LCM of numbers. HCF and LCM are used for conversion of fractions performing operations on them.