Teachers fail primary school simple fraction test

The teachers work for the goverment - need I say more.................
 
In their defense (I don't teach maths)

First thing I did was grab the calculator and came to 0.85 and then tried to convert it back to X/Y.

After that I remembered that it needs to be simplified with the first common which would have been 20 and then work from there.
(1/4; [4x5 = 20]; {1x5 = 5}) = 5/20
(3/5; [5x4 = 20]; {3x4 = 12}) = 12/20

17/20 = 0.85


*I am however out of school now for almost 14 years so I have an excuse :D *
 
This one is so easy... convert to decimal (1/4 = 0.25, 3/5 = 0.6) and add (= 0.85), remember that 0.85 = 85/100, divide numerator and denominator by 5 = 17/20.

Maybe I should be a math teacher... even though I almost failed the subject in Matric!!!
 
MickeyD said:
Kosmik said:
17/20 and it can't be reduced any further ( forgot what the term is where you lower the fraction back to a common number but as 17 is a prime you can't )

Sad to see.
Click to expand...
Fractions - lowest common denominator.
Click to expand...
Lowest common denominator is when you bring the 2 fractions you're adding or subtracting to the same denominator (it doesn't have to be the lowest one but that is easiest). What Kosmik is talking about is simplifying the fraction. Like simplifying 5/10 into 1/2.

Still scary that maths teachers can't do simple fractions. I saw the other day that kids are taught 3 or 4 different methods for multiplying fractions. Nowadays they use this weird matrix of blocks and the kids superimpose the 2 matrices (one for each fraction) and then the common area that overlaps in the matrices is the answer... you know... as opposed to just multiplying top and bottom like I learnt at school... which seems so much simpler.
 
porchrat said:
Lowest common denominator is when you bring the 2 fractions you're adding or subtracting to the same denominator (it doesn't have to be the lowest one but that is easiest). What Kosmik is talking about is simplifying the fraction. Like simplifying 5/10 into 1/2.

Still scary that maths teachers can't do simple fractions. I saw the other day that kids are taught 3 or 4 different methods for multiplying fractions. Nowadays they use this weird matrix of blocks and the kids superimpose the 2 matrices (one for each fraction) and then the common area that overlaps in the matrices is the answer... you know... as opposed to just multiplying top and bottom like I learnt at school... which seems so much simpler.
Click to expand...

Doesn't it matter when you get the concept of multiplication or division with 1 doesn't change the value but allows you to manipulate things? Or has that just added to the confusion?
 
Albereth said:
Doesn't it matter when you get the concept of multiplication or division with 1 doesn't change the value but allows you to manipulate things? Or has that just added to the confusion?
Click to expand...
I'm sorry I honestly don't know what you're saying here.
Could you perhaps reword this.
 
porchrat said:
I'm sorry I honestly don't know what you're saying here.
Could you perhaps reword this.
Click to expand...

When you get into the part of learning that any number multiplied by 1 is the same number, you can then multiply anything by 1 and not change it. With me?

Then you also know that any number divided by itself is also 1. Okay?

So if you multiply 3/5 by 1, you get 3/5.

And if you multiply 3/5 by 4/4 (aka 1) you have 12/20.

And you can go and add that to the other number that you multiplied by 1 (or 5/5).

But I think that is high school math.

Whereas in primary school you'd learn the bit about multiplying the numerator of one by the divisor of the other (and vice versa) and then adding. But I think that is a little trick (that works for two fractions being added) but the high school way is what it's about.

Hope that is clear.
 
Albereth said:
When you get into the part of learning that any number multiplied by 1 is the same number, you can then multiply anything by 1 and not change it. With me?

Then you also know that any number divided by itself is also 1. Okay?
Click to expand...
Not necessarily. Some kids don't make that connection straight away.


So if you multiply 3/5 by 1, you get 3/5.

And if you multiply 3/5 by 4/4 (aka 1) you have 12/20.

And you can go and add that to the other number that you multiplied by 1 (or 5/5).

But I think that is high school math.
Click to expand...
Multiplying fractions isn't high school maths. They cover that in mid to late primary school.


Whereas in primary school you'd learn the bit about multiplying the numerator of one by the divisor of the other (and vice versa) and then adding. But I think that is a little trick (that works for two fractions being added) but the high school way is what it's about.

Hope that is clear.
Click to expand...
Yea but when you're dealing with simple fractions the easiest way to multiply them is just to multiply numerators and denominators. It is surely also the easiest method to teach. You should see the crazy methods they teach kids these days. Colouring in blocks in matrices and then superimposing them? WTF? That approach makes no sense to me. How hard can it be to multiply numerators and denominators... well judging by how many teachers fail these tests I'd say apparently pretty hard.
 
porchrat said:
Not necessarily. Some kids don't make that connection straight away.



Multiplying fractions isn't high school maths. They cover that in mid to late primary school.



Yea but when you're dealing with simple fractions the easiest way to multiply them is just to multiply numerators and denominators. It is surely also the easiest method to teach. You should see the crazy methods they teach kids these days. Colouring in blocks in matrices and then superimposing them? WTF? That approach makes no sense to me. How hard can it be to multiply numerators and denominators... well judging by how many teachers fail these tests I'd say apparently pretty hard.
Click to expand...

It isn't - until you get lots of them and then you figure out that you need to lowest common multiple. Sorry, it is all a blur these days about what I learnt on what day :)

I remember having a bag of wooden blocks. Okay, this was a UK thing because I've never seen it here. I admit that it did make maths fun and you could build cool towers.

The girl child asked how to express irrational fractions as a decimal the other day.

'By using a calculator' isn't the right answer.

Sorry - the bit about multiplying fractions not being high school. True. My point was more about laws of mathematics. I think that is a high school thing. That's why the primary school thing is about showing numerator x divisor and the high school thing is about the awesomeness of 1
 
Last edited:
It's sad that so many people seem to be proud of the fact that they suck at basic maths :/
 
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X