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Does anyone know any real life applications for HCF and LCM. I can think of sorts of questions for example if one light house flashes with 8 second period and one with 12 second period, how often will they both flash simultaneously. This sort of question is contrived. Any real ones?
All ideas gratefully received.
You could try following the topic with adding fractions, where LCM comes in very handy, and which is a bit more obviously applicable.
How about the alignment of planets around the Sun?
Different sized cogs in a machine?
Wanting to use the same group sizes for an activity with 2 different sized classes for HCF.
Less real life but can be fun. For LCM - who will first say Fizz Buzz in different games of Fizz Buzz.
Slightly contrived: rotas. eg you take turns with 3 siblings to load the dishwasher, and the oldest three also have a rota for loading the washing machine. How often do you have to do both? Or shift patterns similarly.
(I knew a school with an 8-day timetable - when do we next have last lesson on Friday?)
I'm not sure this is directly about HCF and LCM, but it is certainly related
http://www.arachnoid.com/prime_numbers/
How organisms develop life cycles based on prime number of years to avoid predation.
grrrr
I like the locust simulation, but it may well confuse students who have only just got round the idea that loci have nothing to do with flying grasshoppers.
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