Maths Q help please

[Surferfish]

Mathematically, making the numerator the sane is not a good approach - it leads to errors and is not advised. I would NEVER suggest it so please don't tell children to do this.

In this question, simplifying the 2/6 to 1/3 means you can order three of them easily
2/6 = 1/3, 1/5, 2/7, 1/4
1/5, 1/4, 1/3 so all we need to decide is where 2/7 goes which make it much easier

Well maybe if we were to rewrite 2/7 as 1/3.5 that might help us decide...

[Guest55]

I suspect that is a very poor joke

It's simple to see where it fits isn't it without constructing non-fractions.

[Surferfish]

Well to be honest it may not be simple to everyone that 2/7 is bigger than 1/4 and smaller than 1/3.

I thought it was a very good suggestion of schalla's to write 2/7 as 1/3.5 as it made it very clear, but you were quite dismissive of it for some reason.

2/7 just means 2 divided by 7 after all doesn't it, so personally I don't see why you shouldn't rewrite this as 1 divided by 3.5 if it helps clarify things?

[Guest55]

By definition a fraction has to have an integer numerator and denominator. So you are constructing a non-fraction; it would not be looked at favourably in an exam and you'd lose marks.

[streathammum]

I don't think anyone was suggesting that you would write the answer with all the fractions having a numerator of 1 - you would write them out as they appeared in the question. It's just that if you can think about them all as being one over something, that will show you which order to write them in.

[Guest55]

Please don't advocate that - it won't be valid in KS3 and is setting up a child to fail.

[Droftaw]

How about giving the DC £100, send them down the bookies to bet on the horses. That’ll sharpen their fractions (and decimals).

[Guest55]

Odds are not expressed as fraction or decimals ....

Perhaps you don't want advice from someone with years of maths teaching behind them who is aware of how misconceptions can arise from so-called 'simple' approaches when the topic develops further?

[anotherdad]

Dividing by zero springs to mind. My primary education taught me that dividing anything by zero equalled zero.

[Guest55]

Classic seen on a Primary classroom wall [commercially bought poster]:

'Multiplication makes the answer bigger, division makes the answer smaller'

OK so 50 x 0.1 = whoops ... 50 divided by 0.1 = whoops

'Two minuses make a plus'
- 4 x -3 = 12 ok yes I agree but -3 -3 = + 6 [no it doesn't]