Mind map
LCM & HCF
Mind map: LCM & HCF
Map content
LCM & HCF
the lowest common multiple is the smallest number that will divide by all the numbers in question
- to find the LCM, list all the prime factors of a number, and then list all the prime factors that appear in both of the numbers, and multiply them all together to find the LCM
- EXAMPLE:
- find the LCM of 18 and 30
- prime factors of 18 = 2 x 3 x 3
- prime factors of 30 = 2 x 3 x 5
- all the numbers that appear are 2, 3, 3, and 5
- 2 x 3 x 3 x 5 is 90, so that is the LCM
- all the numbers that appear are 2, 3, 3, and 5
- prime factors of 30 = 2 x 3 x 5
- prime factors of 18 = 2 x 3 x 3
- find the LCM of 18 and 30
- EXAMPLE:
- to find the LCM, list all the prime factors of a number, and then list all the prime factors that appear in both of the numbers, and multiply them all together to find the LCM
the highest common factor is the biggest number that will divide into all the numbers in question
- list all the prime factors that appear in each number, and find the common numbers and multiply them together to find the HCF
- EXAMPLE:
- find the HCF of 180 and 84
- prime factors of 180 are 2, 2, 3, 3, and 5
- prime factors of 84 are 2, 2, 3 and 7
- common numbers are 2, 2, and 3
- 2 x 2 x 3 is 12, this is your HCF
- prime factors of 180 are 2, 2, 3, 3, and 5
- find the HCF of 180 and 84
- EXAMPLE:
- list all the prime factors that appear in each number, and find the common numbers and multiply them together to find the HCF
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- GCSE Maths (Number) Mind Map on LCM & HCF, created by lizabeth rawson on 21/02/2020.
- Created by
- lizabeth rawson
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