Author Topic: Maths question  (Read 3936 times)

Rhiannon

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Maths question
« on: October 15, 2015, 07:51:49 PM »
When IRL is it necessary to add fractions with different denominators?

Harrowby Hall

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Re: Maths question
« Reply #1 on: October 15, 2015, 08:16:01 PM »
When IRL is it necessary to add fractions with different denominators?

Quite often, I should think, but operationally we usually transform the vulgar fraction into a decimal fraction. How about dealing with relative quantities in cooking?

Has this been prompted by a children's homework question?

The purpose of learning mathematics at school is to acquire logical thinking skills ... not just to operate a calculator.
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Rhiannon

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Re: Maths question
« Reply #2 on: October 15, 2015, 08:26:47 PM »
My eldest's maths teacher has said he can think of no situation IRL when he would need to add together fractions with different denominators, and neither can I. I thought about cooking, but that works more on ratio IME - a 3:1 flour to fat ratio for example, or mostly mince to a little onion. And it isn't something you need do with mathematical precision unless baking a cake to impress Mary Berry.

Incidentally my daughter spent the summer* doing logical thinking problems set by her teacher. She rarely uses a calculator except when instructed to do so to check her work.

* Eta not the whole summer, because that would be weird.
« Last Edit: October 15, 2015, 08:30:41 PM by Rhiannon »

Outrider

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Re: Maths question
« Reply #3 on: October 15, 2015, 08:45:55 PM »
My eldest's maths teacher has said he can think of no situation IRL when he would need to add together fractions with different denominators, and neither can I. I thought about cooking, but that works more on ratio IME - a 3:1 flour to fat ratio for example, or mostly mince to a little onion. And it isn't something you need do with mathematical precision unless baking a cake to impress Mary Berry.

Incidentally my daughter spent the summer* doing logical thinking problems set by her teacher. She rarely uses a calculator except when instructed to do so to check her work.

* Eta not the whole summer, because that would be weird.

Integration and differentiation, which are used when attempting to discern information from equations, often require the ability to manipulate fractions of differing denominations - calculus like this is quite important to various forms of engineering and statistical analysis. Although purely numerical fractions can normally be rationalised relatively easily, the skills of manipulating them are useful when you start to work with irrational components and variables.

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jeremyp

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Re: Maths question
« Reply #4 on: October 15, 2015, 09:00:54 PM »
When IRL is it necessary to add fractions with different denominators?
In maths, frequently, although the denominators are rarely simple numbers.

In the kind of arithmetic most people use in everyday life, not so much, especially now that the imperial system is on its way out at last.
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Rhiannon

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Re: Maths question
« Reply #5 on: October 15, 2015, 10:32:34 PM »
My eldest's maths teacher has said he can think of no situation IRL when he would need to add together fractions with different denominators, and neither can I. I thought about cooking, but that works more on ratio IME - a 3:1 flour to fat ratio for example, or mostly mince to a little onion. And it isn't something you need do with mathematical precision unless baking a cake to impress Mary Berry.

Incidentally my daughter spent the summer* doing logical thinking problems set by her teacher. She rarely uses a calculator except when instructed to do so to check her work.

* Eta not the whole summer, because that would be weird.

Integration and differentiation, which are used when attempting to discern information from equations, often require the ability to manipulate fractions of differing denominations - calculus like this is quite important to various forms of engineering and statistical analysis. Although purely numerical fractions can normally be rationalised relatively easily, the skills of manipulating them are useful when you start to work with irrational components and variables.

O.

How would you use this in daily life? (Genuine question, really have no idea)

Rhiannon

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Re: Maths question
« Reply #6 on: October 15, 2015, 10:34:12 PM »
When IRL is it necessary to add fractions with different denominators?
In maths, frequently, although the denominators are rarely simple numbers.

In the kind of arithmetic most people use in everyday life, not so much, especially now that the imperial system is on its way out at last.

I didn't realise it would apply to Imperial measurements. Otherwise I can't think of anything that couldn't be better served by using percentages or ratio - not that maths is my thing, as you will have gathered.

jeremyp

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Re: Maths question
« Reply #7 on: October 16, 2015, 12:36:42 AM »
Otherwise I can't think of anything that couldn't be better served by using percentages

Multiplying decimals is multiplying fractions. It's just that the fractions are always some power of ten.


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or ratio - not that maths is my thing, as you will have gathered.
Not quite sure what you mean by "ratio".  In my mind, a ratio is a fraction.
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Rhiannon

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Re: Maths question
« Reply #8 on: October 16, 2015, 07:42:47 AM »
Otherwise I can't think of anything that couldn't be better served by using percentages

Multiplying decimals is multiplying fractions. It's just that the fractions are always some power of ten.


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or ratio - not that maths is my thing, as you will have gathered.
Not quite sure what you mean by "ratio".  In my mind, a ratio is a fraction.

It's what I said earlier about cake or pastry making - you know you need twice or three times the amount of flour for every unit of fat. But of course that is sometimes expressed as 'half fat to flour'.

Yes, we get the thing about fractions and decimals being the same. But I think most of the time we'd convert into decimal before adding. Even then I can't think of a reason why the original fractions would have different denominators - not in everyday maths.

Harrowby Hall

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Re: Maths question
« Reply #9 on: October 16, 2015, 08:59:41 AM »
Your last answer, Rhi, has got me thinking.

When we used sd (old money, real money etc) were we not often provided with different "types" of fraction that we sometimes used concurrently - half a crown, eighteen pence, five guineas and so on?

And when we counted up a column of values involving twelve pence in one shilling and twenty shillings in one pound were we not - in reality (since the total of pennies had to be converted into shillings) - adding fractions?
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Outrider

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Re: Maths question
« Reply #10 on: October 16, 2015, 09:03:59 AM »
How would you use this in daily life? (Genuine question, really have no idea)

Engineering, computer programming, any sort of statistical analysis... it really rather depends on what job you want to do.

Outside of work situations, of course, probably not so much.

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Udayana

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Re: Maths question
« Reply #11 on: October 16, 2015, 02:34:08 PM »
Of course you can always do arithmetic in decimal or rearrange the operations to avoid the fractions or approximate where appropriate.

Using different denominators hmm . consider calculating how long a journey would take if the route involved 57 miles along a road with expected speed 30 mph and 157 miles along a motorway at 70mph:

Total time in hours = 57/30 +  157/70
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jeremyp

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Re: Maths question
« Reply #12 on: October 16, 2015, 10:54:36 PM »

It's what I said earlier about cake or pastry making - you know you need twice or three times the amount of flour for every unit of fat. But of course that is sometimes expressed as 'half fat to flour'.

This is all definitely fractions by another name. If you see a recipe that says 1/2 as much fat as flour but it also says 1/2 pound of flour, you know how much fat and flour you need to put on the scales, yes? Well, that is adding two fractions.

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yes, we get the thing about fractions and decimals being the same. But I think most of the time we'd convert into decimal before adding.
Nothing wrong with that. You convert one problem into a different problem that you know how to solve. Mathematicians do that sort of thing all the time.
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Rhiannon

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Re: Maths question
« Reply #13 on: October 16, 2015, 11:28:12 PM »
I dare say you are right, Jeremy.  :)

Floo

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Re: Maths question
« Reply #14 on: October 17, 2015, 04:21:35 PM »
Where maths is concerned I pass! Thank goodness for calculators, without mine for even simple sums, I would be completely up the creek without the paddle!
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Harrowby Hall

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Re: Maths question
« Reply #15 on: October 17, 2015, 04:48:15 PM »
How can you be sure the calculator is giving you the right answer?
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ad_orientem

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Re: Maths question
« Reply #16 on: October 22, 2015, 08:03:51 PM »
When IRL is it necessary to add fractions with different denominators?

Quite often, I should think, but operationally we usually transform the vulgar fraction into a decimal fraction. How about dealing with relative quantities in cooking?

Has this been prompted by a children's homework question?

The purpose of learning mathematics at school is to acquire logical thinking skills ... not just to operate a calculator.

The calculator is one of the bestest inventions ever. Why do it in your head when you can use a calculator? Never liked maths. It's rubbish. 😁
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jeremyp

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Re: Maths question
« Reply #17 on: October 22, 2015, 08:13:46 PM »
When IRL is it necessary to add fractions with different denominators?

Quite often, I should think, but operationally we usually transform the vulgar fraction into a decimal fraction. How about dealing with relative quantities in cooking?

Has this been prompted by a children's homework question?

The purpose of learning mathematics at school is to acquire logical thinking skills ... not just to operate a calculator.

The calculator is one of the bestest inventions ever. Why do it in your head when you can use a calculator? Never liked maths. It's rubbish. 😁

Calculators do not help with maths, they only help with arithmetic which is not the same thing.

As to whether maths is rubbish or not, clearly it is not because without it, the modern World would look very different. Maths is far more important than any crappy religion, of which yours is one.
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BashfulAnthony

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Re: Maths question
« Reply #18 on: October 22, 2015, 08:17:13 PM »
When IRL is it necessary to add fractions with different denominators?

Quite often, I should think, but operationally we usually transform the vulgar fraction into a decimal fraction. How about dealing with relative quantities in cooking?

Has this been prompted by a children's homework question?

The purpose of learning mathematics at school is to acquire logical thinking skills ... not just to operate a calculator.

The calculator is one of the bestest inventions ever. Why do it in your head when you can use a calculator? Never liked maths. It's rubbish. 😁

Calculators do not help with maths, they only help with arithmetic which is not the same thing.

As to whether maths is rubbish or not, clearly it is not because without it, the modern World would look very different. Maths is far more important than any crappy religion, of which yours is one.

What an eloquent and well-worded argument  -  you ought to be on Question Time!
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jeremyp

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Re: Maths question
« Reply #19 on: October 22, 2015, 08:25:53 PM »

What an eloquent and well-worded argument  -  you ought to be on Question Time!

Thank you. That makes a change from your usual whining.
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BashfulAnthony

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Re: Maths question
« Reply #20 on: October 22, 2015, 08:31:31 PM »

What an eloquent and well-worded argument  -  you ought to be on Question Time!

Thank you. That makes a change from your usual whining.

No, thank you, for replying without a swear word in sight.   ;)
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It is my commandment that you love one another."

ad_orientem

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Re: Maths question
« Reply #21 on: October 22, 2015, 09:06:35 PM »
When IRL is it necessary to add fractions with different denominators?

Quite often, I should think, but operationally we usually transform the vulgar fraction into a decimal fraction. How about dealing with relative quantities in cooking?

Has this been prompted by a children's homework question?

The purpose of learning mathematics at school is to acquire logical thinking skills ... not just to operate a calculator.

The calculator is one of the bestest inventions ever. Why do it in your head when you can use a calculator? Never liked maths. It's rubbish. 😁

Calculators do not help with maths, they only help with arithmetic which is not the same thing.

As to whether maths is rubbish or not, clearly it is not because without it, the modern World would look very different. Maths is far more important than any crappy religion, of which yours is one.

Oooo! ::) Of course maths has its uses but for me I think it's rubbish. I just can't get my head round it. I hate calculations. They're for boffs. At school I was always more an English, history and geography person. English I loved especially.
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jeremyp

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Re: Maths question
« Reply #22 on: October 22, 2015, 09:56:07 PM »
Of course maths has its uses but for me I think it's rubbish.
No it isn't even for you.

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I just can't get my head round it. I hate calculations.
Ah, you aren't any good at math,therefore maths is rubbish. Has it not occurred to you that, actually, it is you that is rubbish (at maths)? Would it be acceptable for me to say "music is rubbish" just because I am completely inept at any musical instrument?

Quote
They're for boffs. At school I was always more an English, history and geography person. English I loved especially.
It's interesting that people who are illiterate tend to be highly embarrassed about it, but people who are innumerate seem to wear it as a badge of pride.
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ad_orientem

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Re: Maths question
« Reply #23 on: October 22, 2015, 10:09:27 PM »
Of course I'm rubbish at maths. My brain just doesn't work that way.
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Harrowby Hall

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Re: Maths question
« Reply #24 on: October 22, 2015, 10:17:08 PM »
Oooo! ::) Of course maths has its uses but for me I think it's rubbish. I just can't get my head round it. I hate calculations. They're for boffs. At school I was always more an English, history and geography person. English I loved especially.
,

Mathematics is not what you think it is.

All you know is arithmetic ... and, if what you say is correct, you do not even have the skill to know whether the result your calculator shows is correct or not. If you hate calculations then you cannot be aware of all those occasions that shopkeepers have short changed you. How sad.

Mathematics is about thinking and using symbolic logic to solve problems. Mathematics is universal.
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