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#1 2005-02-09 19:35:59

katey
Guest

maths

can you tell me good  web pages for maths plus can you  help me with fractions the times  it is really hard and i always get them wrong

#2 2005-02-09 21:11:01

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,529

Re: maths

Well, we like this website! (Of course)

We have some pages here that tell you how to deal with fractions. Adding, subtracting multiplying and dividing.

For example, to multiply 1/4 by 2/3 you just multiply the top bits by the bottom bits:

1/4 x 2/3 = 1x2 / 4x3  = 2/12.

2/12 can be simplified to 1/6

You can read more about this at Multiply Fractions


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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#3 2005-02-10 05:48:37

Barker
Member
Registered: 2005-02-10
Posts: 2

Re: maths

My daughter's homework is can you write down the properties of a cube?  It is a 3D cube.   Is the answer 12 sides.

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#4 2005-02-10 08:38:56

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,529

Re: maths

A 3D cube is just a simple box. So it has a top and a bottom, a front and back and a left and right side. In othe words just 6 sides. But if you count the edges, there are 12.

You can find out more here: Platonic Solids


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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#5 2005-02-12 05:12:43

msg21252
Member
Registered: 2005-02-12
Posts: 1

Re: maths

need formula on how to figure percentages from a whole number example:  total amount for item is $3500.00, Joe's 20% is included in this number. How much does Joe get?

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#6 2005-02-12 10:47:43

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,529

Re: maths

Percentages just mean "per 100" so 20% means "20 per 100"

Your particular problem MAY be as simple as calculating 20% of 3500, (which is 20/100 x 3500 = 20 x 3500/100 =  20 x 35 = $700)

But perhaps they mean "there was a price, Joe got 20% of that, and the total is $3500"

In that case it is a little harder.

You would figure it this way: you know that $3500 = "The Unknown Price" + 20% of  "The Unknown Price" =  120% of the unknow price.

And 120% is 120/100, which is really just 1.2

So, "The Unknown Price" x 1.2 = 3500

Dividing both sides by 1.2 gets:

"The Unknown Price" x 1.2 / 1.2  = 3500 / 1.2

"The Unknown Price" = 3500 / 1.2

"The Unknown Price" = 2916.67

And Joes 20% would be 20/100 * 2916.67 = 583.33

(Confirming this: 2916.67 + 583.33 = 3500)

Was that a help?


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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