HCF or Highest Common Factor (a.k.a Greatest common factor) refers to
a set of two or more different numbers that can be divided by exactly
or a common number. HCF is also called as GCD/GCM – Greatest Common
Divisor, Greatest common denominator, or Greatest Common Factor.
LCM or Least Common Multiple refers to the smallest quantity of number that is divisible by two or more given quantities of number without a remainder: 12is the least common multiple of 2, 3, 4, and 6. LCM is also called as Lowest Common Multiple. LCM is the smallest number that is multiple of two or more numbers.
HCF and LCM are calculated by either factorization method or division method.
If number ‘a’ divided another number ‘b’ exactly, then we say that
‘a’ is a factor of ‘b’.
In this case, ‘b’ is called a multiple of ‘a’.