Lowest Common Multiple (LCM)
This lesson covers:
- How to find the lowest common multiple (LCM) of a pair of numbers, by comparing lists of each number's multiples
- How to find the LCM of a pair of numbers by comparing their prime factors.
Find the lowest common multiple (LCM) of 6 and 10
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Find the lowest common multiple (LCM) of 3 and 6
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Find the lowest common multiple (LCM) of 4 and 7
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A red light flashes every 6 seconds. A yellow light flashes every 4 seconds.
After first being turned on, how long will it be until they both flash at the same time?
seconds
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Claire is organising a BBQ and wants to cook hot dogs. Each bag of bread rolls contains 18 rolls, and each packet of sausages contains 15 sausages.
If Claire wants to use every single bread roll and sausage she buys, what is the smallest number of hot dogs she will need to cook?
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Below are the numbers 120 and 150, expressed as products of their prime factors:
120 = 2 x 2 x 2 x 3 x 5
150 = 2 x 3 x 5 x 5
Use these to find the lowest common multiple (LCM) of 120 and 150.
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Below are the numbers 84 and 120, expressed as products of their prime factors:
84 = 2 x 2 x 3 x 7
120 = 2 x 2 x 2 x 3 x 5
Use these to find the lowest common multiple (LCM) of 84 and 120.
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