# Factors Investigation

Discussion in 'Primary' started by Gloriousness, Jan 20, 2010.

1. ### GloriousnessNew commenter

Looking at the factors work I have planned for tomorrow, it's all ****. Therefore I'm wondering if anyone has ideas on an investigation or anything to do with the factors of a number. It doesn't matter what year group it's for (this is for high ability Year 5), as I can happily scale it up. I'm just at a loss for an original idea.

2. ### orb1

Investigate do all numbers have an even number of factors? Then you can link to prime and square numbers.

3. ### Irulan

Have you looked at the factor bugs lesson on teachers' tv? It was actually designed for year 5. I did it with my year 4s and scaled down (more explaining). It was really good and I will go back to it. Attached to the video (which is worth watching) is the lesson plan. Really easy to do and great fun. Should stretch the able ones too.

4. ### Andrew JeffreyNew commenter

Here's one I have used with good Year 5s.

Give them lots of cubes. Ask them to make as many different rectangles as they can using two cubes. Discuss the 2 options (2 by 1 or 1 by 2). Agree that these are not different.

This means that 1 and 2 are all the factors of 2.

Now give them another cube. Again, there is only one possible rectangle that can be made from these, a 3 by 1, so 3 has two factors: 1 and 3.

Now give them a fourth cube. This time they can make 2 different rectangles: a 4 by 1 and a 2 by 2. So 4 has 1,2, and 4 as factors.

Now give them a fifth cube. And so on. Up to 20, preferably.

This is great because they get to find the factors of all the numbers up to, well, whatever you want to go to. Then ask them which numbers have exactly 2 factors. They will say (hopefully, having made and recorded the rectangles onto squared paper): 2,3,5,7,11,13,17 and 19. Look familiar?

Even better, ask them which numbers have an ODD number of factors. Guess what? They will say 1,4,9,16. Another familiar looking set of numbers, with luck!

It is quite easy to prepare - you just need some counters, some squared paper, pencils and rulers. PLEEEEEEASE don't make this an IWB activity other than to introduce the activity - it must be done in pairs and practically to derive the maximum benefit.

I can't claim any originality for this activity - I read it in a book about 20 years ago!

5. ### Andrew JeffreyNew commenter

Sorry - I don't know why all my paragraph marks were ignored - I realise it must be hard to read. Apologies, and also to Orb1 whose idea is similar but whose post was posted before I had finished typing!

7. ### Andrew JeffreyNew commenter

Here is the link that Irulan mentions: http://www.teachers.tv/video/37869

8. ### alea

In previous years I have always left factors for supply!! Will look forward to teaching it now! Have lower set year 5 but this is such a simple and easy way to explore what I had considered a very dry area.
Many thanks!

9. ### Andrew JeffreyNew commenter

If you have Numicon, there is a brilliant lesson on the training DVD as well. It's aimed at Y6 but I think most Y5 would cope well with it.

10. ### alea

Don't have Numicon, is that different coloured holey stuff? Would you recommend? Not that I have any money

11. ### Andrew JeffreyNew commenter

Yes, that's the stuff! I would recommend but I would also qualify that by saying that I deliver training for them so my view is not an impartial one.

(I would add though that even if I didn't work for them I honestly would recommend Numicon unreservedly.)

12. ### alea

Thanks Andrew, our SENCO was talking about buying some for reception, I will investigate!

13. ### cgibbon

Thanks Andrew,
I have a very kinsthetic class of Year 5's and this looks perfect for a factors lesson - I'm planning opn using it tomorrow.