Highest common factors (HCF) and lowest common multiple (LCM)
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Highest Common Factors (HCF)
This is the highest or largest factor that is common to the numbers in question.Â
For example let's find the HCF of the numbers 24 and 40.
The factors of 24 are 1, 2, 3, 4, 6, 8, 12 and 24
The factors of 40 are 1, 2, 4, 5, 8, 10, 20 and 40
Therefore, the highest common factor (HCF) of 24 and 40 is 8.
** remember factors are always equal to or smaller than the number in question.
Lowest Common Multiple (LCM)
This is the lowest or smallest multiple that is common to the numbers in question.
For example, let's find the LCM of the numbers 24 and 40.
Multiples of 24 are 24, 48, 72, 96, 120, 144...
Multiples of 40 are 40, 80, 120, 160...
Therefore, the lowest common multiple of 24 and 40 is 120.
** remember multiples are always larger than the number in question.
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