# Product of Primes - real life link?

Discussion in 'Mathematics' started by smiley_emma100, Apr 3, 2011.

1. ### smiley_emma100

I'm delivering an observed lesson to top set year 7's on expressing a number as a product of its primes and I'd really like to make the lesson a little more functional/relevant to real life - but for the life of me cannot think of an interesting real life application of product of primes, does anyone know of one? Thank you in advance

2. ### Betamale

Why?
Why does everything have to have a reason behind learning it beyond needing it for further aspects of maths? or for intrinsic reward? The intrinsic desire to better themselves, build the blocks of good maths and enjoy success is enough of a reason to learn.
You can tell them that many financial transactions use algoriths based on primes but do they need to know that? will it making learning more 'cool' and 'functional'?
"You are learning this because its fun and it will make you far more efficient when you as top set students are doing 'harder maths' further up the school"
Please can people move away from having to justify why we learn everything. We learn for so many reasons and should not have to link everything to imspire kids or make learning worthwhile and try and keep them interested.
Some aspects of maths are very functional, other lead to it and creating a circus act is not required for them, for the observer and the good of all. I once 'hid behind the sofa' when a trainee suggested we teach it beacuse it will help when playing darts and how to check out...
Teach functional maths, leave number work alone IMO

3. ### MasterMaths

Short of going into some very high level coprime work which is (or, at least was, but it may have moved on in recent years) central to certain areas of cryptography, I'm not sure there are many "real" real life situations.
Happy to be proven wrong though.

4. ### bombaysapphireStar commenter

You can use them to work out exactly how many factors a number has.
That's probably not as "real life" as you are looking for but I don't believe that everything students learn in Maths needs to have an immediate application in real life.

5. ### pipipi

I'm not sure it's to do with products, but with prime numbers there are some great uses for making things secure on the internet. Try Simon singh's explanation in The Codebook.

6. ### valed

I've got an idea!
Let's shoot an Ofsted inspector and an Advisor at the same instant
If we shoot any Ofsted inspector every 5 minutes and an Advisor every 8 minutes, how long will it be before we each shoot an Inspector and an Advisor at the same time?

Not soon enough I hear you all cry!!!!!!!!!!!!!!!

7. ### MathsHOD

Like it!

Sounds like a lesson I do when introducing LCM - I have 2 loops of BRIO train tracks. One has 8 pieces and the other has 14. The only way that people can get off one loop and onto a train on the other is at a station that they share.

2 trains start at the station and head off at 'one piece of track per move' - when will they next get back to the station at the same time? (No stopping and waiting allowed).

Swap the 8 loop for a 10 loop and repeat.

Eventually students spot a pattern and then leads into LCM in a more formal sense.

8. ### pixelNew commenter

GIMP and Mersenne Primes always gets my classes talking. There is cash in it!

9. ### Polecat

Just wondering what pattern you are seeing.
There is the fact that most primes are in the 1 and 5 columns.
More likely it is the deletion of composites using verticals and diagonals.

10. ### pipipi

Maybe pattern is the wrong word to use.
Most primes are in the 1 and 5 columns.
And isn't there a proof about ALL prime being multiples of 6 plus/minus 1?

I certainly found it enlightening to notice/realise that primes were always adjacent to a multiple of 6, and wondered why that was. I suppose it was just me having only ever done it in 10s so primes seemed to be rather random (obviously not in the evens columns) and then seeing that they only cam up in those two particular places seemed stunning to me.