HCF and LCM Formulas

Important Points and Formula :

1. Factors : If a divides b exactly, we say that a is a factor of b.

For example : 6 = 1 X 6 = 2 X 3

i,e 6 is divided by 1, 2, 3 and 6 completely. ∴ 1, 2, 3, 6 are the factors of 6

2. Multiples : If a divides 6 exactly, then b is the multiple of a

For example : 5 X 1 = 5

5 X 2 = 10

5 X 3 = 15

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5, 10, 15 .... are completely divided by 5.

∴ 5, 10, 15, .... are the multiples of 5

3. H.C.F : The H.C.F of two or more than two numbers is the gratest number that divides each of them exactly.

4. L.C.M : The last number which is exactly divisible by each one of the given numbers is called their L.C.M

5. Co-primes : Two numbers are said to be co-prime if their H.C.F is 1

Example : 6 and 7 are co-prime.

6 = 1 X 6 = 2 X 3 7 = 1 X 7

∴ H.C.F = 1

6. Product of two numbers = Their H.C.F X Their L.C.M

7. H.C.F of fractions =	H.C.F of numerators
	L.C.M of denominators

8. L.C.M of fractions =	L.C.M of numerators
	H.C.F of denominators