Dividing fraction - how do they teach? (1 Viewer)

jet

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Although fustrating, the high you get from being mentally fustrated and leading to a correct answer is the best.
That is true. Its the best.

I went to a very small primary school (the year 6 class was 16 kids in total), and I found that I was extremely unprepared in maths when I went into year 7. I found that where I didn't know a thing everyone else knew it. I didn't even know how to multiply/divide fractions
I do remember how multiplication was taught in year 1. We were each given some cards and objects and (for example with 2 x 2) to make '2 groups of two'. This helped with the concept of multiplication. But after that, all that happened was drills in the multiplication tables.

We had the best teacher for 4 unit. We would derive everything and have in depth discussions. It was great, and I kind of miss it.
 

hermand

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When I read the NSW mathematics syllabus, it stated that kids at stage 2-3 in middle primary school should start to develop their own methods along with methods taught by teachers. I thought if kids are really like that, they would all become PhDs by the time they reach University. Perhaps that's the ideal world that never exists.
my mum is a primary school teacher and one day saw me doing my maths homework when i was younger, and i was doing it a way she didn't recognise, and she got me to do another problem and watched me do it, and i'd developed my own methods for all different types of questions. so it does happen, but that's only because maths was my best subject. but i'm in year twelve now and there is no chance i'll become a phd in the next year, or four for that matter.

but, with the invert and multiply, i always think of it as a fraction over a fraction, and it makes sense. eg, 2/3 all over 5/3 the denominators cancel out and you're left 2/5, the same result as inverting and multiplying. it makes it easier with a common denominator, so you just multiply both fractions until you have one and it all cancels. makes sense in my mind anyway haha.

and i do agree, not many primary school/year seven or eight students would care about the origins of mathematics, many of them are only there because they have to be, and even those who choose to do 2 unit, or general, in hsc years only do it because they feel obligated to do maths because that's what everyone else does, and it's assumed knowledge in many uni courses.

for me though, maths=happiness, so i'd find all that stuff interesting =]]. i like teachers who make me figure things out for myself though, and i have a teacher who tells us pretty much everything in maths for hsc, so that's disappointing. but hey, here's hoping that it's more interesting in uni =]].
 

oasfree

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for me though, maths=happiness, so i'd find all that stuff interesting =]]. i like teachers who make me figure things out for myself though, and i have a teacher who tells us pretty much everything in maths for hsc, so that's disappointing. but hey, here's hoping that it's more interesting in uni =]].
You are going in for a bit of fun but most kids going in for a shock. On the first day, you land in a lecture theatre taking 300-500 freshmen at the same time. The lecturer talks to all and there will be no conversation. Essentially the lecturer only run through main ideas and address very few details. Students swim or drown in University. Those who did not learn how to derive, create and explore will drown.

There is no hand holding at all. There is no mercy when it comes to the marks. If you get 20%, that's what you get as University is not the place to hide results for the sake of good stats. Generally if you fail a subject 2 times with bad grades, you may be banned from taking it again.
 

hermand

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yay for only having one year of school left =]].

are you american?
 

shady145

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yea ive been to 9 schools, (6 primary, 3 high schools). in primary i was tought by most schools to divide by using the system where u place the number out front or a root looking thing.(u should no what im talking about)
like this
5(root looking thing)34
u would do 6 remainder 4
i didnt learn inverse and multiply until yr 7,
at the school i go to now, we derive most things. my 2u teacher just says this is for *shady145's benefit*(coz im the only 1 in my school who does 4u) coz it will be handy for 4u.
 

oasfree

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yay for only having one year of school left =]].

are you american?
No I am not American. I came from Asia long ago. I was doing my HSC in the 80s. I recently investigated math tests from US and Singapore just out of interest. I realise that US math tests are better as they are deeper and broader and seem to focus a bit more on interpretation of data. Generally 1 year ahead of Australian tests. Singapore tests are cunning and much deeper with too much emphasis on algebra and look like 2 years ahead of Australia.

From what I have heard you guys will find Asian overseas students coming at year 10, 11 and 12 are tough in math. They virtually completed 4u back home, spend one year here to relax and improve English before redo 4u here. US students finish their real schooling at year 11 (year 12 mainly for prep for Uni), they start hard work since year 8-9 rather than year 11 like Australia.

When you get to Uni, it's tough. If you do 4u, you will repeat much of the work in 1st year Uni. So first semester is piece of cake, but soon after that they start to drill on the depth of knowledge on question "why" and also on proof of concepts and completeness (how ideas connect and look consistent). It will require a lot of deep thinking about validity and limitation of mathematical theories. You will enjoy stuff like Russell paradox on set theory.

If you are interested in more math I would suggest a degree that combines math, computer science and philosophy. These 3 fields together will help you to investigate the foundation of human knowledge, limit of truth, existence of God, and still leave you room for making decent money (using computer science). It would not hurt to do a little of social stuff in first year like psychology or some art subjects for fun. Lots of pretty giggling girls are in this kind of area. If you are a boy, it's great to have a bit of balance hanging around those giggling girls that have no interest in math and science.

Good luck!
 

the-derivative

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At school I was taught the invert and multiply method. However at my coaching college I've been taught (and this is the only method I use):

a/b divided by c/d
= a/b/c/d

Therefore times the top and bottom together and times the two middle values and you get:

ad/bc.
 

oasfree

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yea ive been to 9 schools, (6 primary, 3 high schools). in primary i was tought by most schools to divide by using the system where u place the number out front or a root looking thing.(u should no what im talking about)
like this
5(root looking thing)34
u would do 6 remainder 4
i didnt learn inverse and multiply until yr 7,
at the school i go to now, we derive most things. my 2u teacher just says this is for *shady145's benefit*(coz im the only 1 in my school who does 4u) coz it will be handy for 4u.
I taught my kid math from grade 2. By grade 3, the kid already started to correct the poor teachers every time they made a silly mistake. I found that a good sense of fraction and ratio together forms a powerful platform for the kid to advance in math. Ratio ties things together in a proportional relationship. One great way to teach kids is to bake a cake together! The ingredients must go into the bowl in correct proportion and you just have to proportionally increase to make more cakes to serve more people.

This knowledge forms the basis for deriving both fraction multiplication and fraction division. This leads to the rule that if you multiply both numbers that are locked into a ratio, you don't change the fraction's real value. This knowledge supports the derivation of the "invert & multiply" rule

(a/b) / (c/d) = (a/b)d / (c/d)d = (ad/b) / c = (ad/b)b / bc = ad / bc = a/b x d/c

My kid at the start of grade 4 made up a joke about this lesson

Division of fraction is AD/BC that means After Christ / Before Christ

I reckon this is pretty clever. My kid is in top 1% of UNSW math competition last year and keep pulling ahead. We have a rule of "no learning" during holidays. After each holiday, my kid's math ability improves for no reason (instead of forgetting). It looks like the kid just realises new math application while playing or thinking about life. I think my teaching method (very different to most teachers) has something to do with this. This year my kid joins an OC class at year 5. I worry that they will insist to move the kid to a HS next door for math enrichment. I don't like having a little kid sitting next to big kids who already start to play kissy games.
 

hermand

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This year my kid joins an OC class at year 5. I worry that they will insist to move the kid to a HS next door for math enrichment. I don't like having a little kid sitting next to big kids who already start to play kissy games.
they shouldn't. i was in oc and we had some pretty bright kids, and they didn't put them in hs. one girl left because she thought she was too good for our class and went into year six, but that's the only case i've heard of acceleration.
 

oasfree

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they shouldn't. i was in oc and we had some pretty bright kids, and they didn't put them in hs. one girl left because she thought she was too good for our class and went into year six, but that's the only case i've heard of acceleration.
I went to orientation day. The teacher said that one kid already got moved to HS next door for enrichment in math. The problem is that this only encourage the kid to specialise too much in math at the expense of many other things. The kids should spend less time in math and try to excel in other things which are even more difficult like science. In OC class, they often have composite 5-6. That means acceleration is within same class. The kid can sit for selective school test early and jump to year 7. But again I don't like acceleration. Kids should be allowed to spend time with other kids as school is for growing up, making friends and try to create good memories.

They don't share the view that advanced math is not math for older kids. Advanced math is more about understanding deeply and discover math by yourself. For example, if a kid is normal, teach the kid how to work out the hypotenuse of a rectangle. If the kid is really advance try to help the kid to find out how to derive the formula to work it out or find another way to work it out. Therefore, just by giving them harder tasks related to same topic, they will be challenged. Also they could be given some work to do such as helping other kids. As they learn to teach a little, they develop further insight about how other people's mind work.
 

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