How to do this one

jupiter00

You've helped me here before, so here goes. 7/9 of animals are sheep on a farm, he sold 3/4 of the sheep, what fraction of farm animals did he sell?

gerry87

Pick a number and use that for the total number of animals, then try and work out the different bits.

MathsManiac

And it would help if you picked a number that it would be easy to get the necessary fractions of... like 36, for example.

Delphi91

If 7/9 are sheep and he sells 3/4 of those, then he has sold 3/4 of 7/9 which is:

3/4 x 7/9 = (3 x 7)/(4 x 9)

= 21/36

= 7/12

FoxT

the point is, to help the op develop his math skills, not to spoonfeed the op with the answer...

TheUsual

Here's a few tips for maths ...

Don't ask random people on the internet what the answer is.
Listen in class.
Ask a student in your class that is good at maths how he/she did it.
Read your maths school books (a lot) if you have a bad maths teacher.

LeixlipRed

Delphi91 wrote: »

If 7/9 are sheep and he sells 3/4 of those, then he has sold 3/4 of 7/9 which is:

3/4 x 7/9 = (3 x 7)/(4 x 9)

= 21/36

= 7/12

Please read the charter. While it might be fun for you to work it out and amaze us with your multiplication skills the OP might prefer to work it out themselves.

TheUsual wrote: »

Here's a few tips for maths ...

Don't ask random people on the internet what the answer is.
Listen in class.
Ask a student in your class that is good at maths how he/she did it.
Read your maths school books (a lot) if you have a bad maths teacher.

I would imagine the OP was just curious or seen the problem somewhere. We're not dealing with a 6 year old child here so drop the condescension please.

TheUsual

LeixlipRed wrote: »

I would imagine blah blah blah

Could you please repeat that in bold please, I can't read normal text. Thanks.

Please ban me to make your week. If it makes you feel important.

LeixlipRed

Oh sweet jesus.

jupiter00

I didn't mean to start WW3! but thank you for helping me and I don't find it insulting Delphi 91 for your example. I am not a child but a concerned mother of a sixth class student and its a while since I did fractions! She is a good student and when we get assistance here we are delighted. People were so helpful last time. I have another problem, I'm almost nervous abous putting it up now......... but
4/9 0f children are boys, there are 8 more girls than boys, how many boys attend the school? The teacher said to skip this one but it will probably come up in another guise so any help here would be great!

Pherekydes

jupiter00 wrote: »

4/9 0f children are boys, there are 8 more girls than boys, how many boys attend the school? The teacher said to skip this one but it will probably come up in another guise so any help here would be great!

Draw a picture!

Draw a circle and divide it up in 9 parts. Shade in the boy bits and girl bits (different colours). See if anything occurs to you or your child. Post back any ideas for more hints.

jupiter00

Hello Pherekydes, School closed early today so we are trying this out. At the risk of being wrong............ how about after trying this visual approach (we are both visual learners) 4/9 = boys and 5/9 = girls so 1/9 =8 the difference? So 4x8= 32 boys?

sullanefc

jupiter00 wrote: »

You've helped me here before, so here goes. 7/9 of animals are sheep on a farm, he sold 3/4 of the sheep, what fraction of farm animals did he sell?

Hi, maths teacher here. New to the forum and its my first post.

One rule in maths that might help here. Whenever you see the word 'of' in fractions, its always multiply. So 3/4 of 7/9 = 3/4 x 7/9

jupiter00 wrote: »

I didn't mean to start WW3! but thank you for helping me and I don't find it insulting Delphi 91 for your example. I am not a child but a concerned mother of a sixth class student and its a while since I did fractions! She is a good student and when we get assistance here we are delighted. People were so helpful last time. I have another problem, I'm almost nervous abous putting it up now......... but
4/9 0f children are boys, there are 8 more girls than boys, how many boys attend the school? The teacher said to skip this one but it will probably come up in another guise so any help here would be great!

jupiter00 wrote: »

Hello Pherekydes, School closed early today so we are trying this out. At the risk of being wrong............ how about after trying this visual approach (we are both visual learners) 4/9 = boys and 5/9 = girls so 1/9 =8 the difference? So 4x8= 32 boys?

That is how I would have done it.

Pherekydes

jupiter00 wrote: »

Hello Pherekydes, School closed early today so we are trying this out. At the risk of being wrong............ how about after trying this visual approach (we are both visual learners) 4/9 = boys and 5/9 = girls so 1/9 =8 the difference? So 4x8= 32 boys?

That's correct. With a lot of maths problems a diagram can help a lot.

jupiter00

Thanks everyone and thanks for the private messages too! I just want to have my children have a positive attitude to maths, its so easy to give up and say 'I'm no good at maths' Some one said its like a chain if you miss out the 'links' in say 3rd/4th class, (fractions, %, decimals....) keep coming back again at a more challenging level. She has a good teacher now who shows that %, decimals, fractions are linked, perhaps obvious, but the teaching of maths makes all the difference. We will probably be back again.......... We know now I've friends here!

Fremen

Questions like the one you just posted are crucial, since they're the first contact your child will have with algebra, even if it's not explicitly stated that algebra needs to be used.

If we let X denote the total number of children and let * represent multiplication, what you've done is solve the equation

(5/9)*X - (4/9)*X = 8,

since the number of girls is (5/9)*X and the number of boys is (4/9)*X.

The junior cycle maths syllabus is just algebra and geometry (or it was when I was a kid), so a good initial understanding of algebra gets you halfway there.

gondorff

sullanefc wrote: »

One rule in maths that might help here. Whenever you see the word 'of' in fractions, its always multiply. So 3/4 of 7/9 = 3/4 x 7/9

True. And helpful, but I think it's more important to teach why you are multiplying the two fractions.

MathsManiac

sullanefc wrote: »

One rule in maths that might help here. Whenever you see the word 'of' in fractions, its always multiply.

Not sure that I agree with that. e.g.: "There were 24 children in a class. A teacher decided to share 2/3 of a box of sweets equally among 3/4 of the children in the class. What fraction of the box did each of these children receive?"

Five "of"s there, so I guess I need to be doing four multiplication sums.

gondorff wrote: »

...but I think it's more important to teach why you are multiplying the two fractions.

I definitely agree with that.

LeixlipRed

I'd agree that it's dangerous to use generalisations like that. A common error you see with 1st year undergraduates is using multiplication when dealing with notation like f(x) or f(g(x)) or anything involving the word "of" when related to functions or composition of functions. Best steer clear of generalisations like that and actually get to the root of what the fractions and the problem represent.