Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

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**sian****Guest**

i hate maths i find it sooo boring!!!

i wanna know what 2 fifths is plz help meeeee!!

**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,646

2 fifths is 2/5 ...

Get a pizza, slice it into 5 pieces, eat two of them and you have eaten 2 fifths. You should also not be hungry any more.

2 fifths is also 4/10ths (or 0.4 in decimal) ... how?

If before eating your 2 slices of pizza, you had cut each of the 5 slices into half, you would have been looking at 10 smaller slices, and you would then eat 4 of these smaller slices.

So, cutting the pizza into 10 slices and eating 4 is the same as cutting it into 5 slices and eating 2.

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

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**K.Cheetham****Member**- Registered: 2005-01-22
- Posts: 5

An angle under 90 Degrees is called an acute but what would the angle be called if over 90 Degrees? please Admin i need to know.

K.Cheetham

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,646

an angle over 90 Degrees is simply called an "obtuse angle"

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

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**K.Cheetham****Member**- Registered: 2005-01-22
- Posts: 5

After obtuse is there anymore?

K.Cheetham

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,646

Angles start at acute, then when they reach 90 degrees it is called a "right angle", more than 90 is obtuse, until 180 degrees which is called a "straight angle".

Note: it must be *exactly* 90 degrees to be a right angle, and it must be *exactly* 180 degrees to be a straight angle.

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

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**amy****Guest**

I absolutely hate maths. I thought i was getting better at it, but i proved myself wrong. What can i do to improve my maths skills? It is sooo hard. Please reply somebody!!! From Amy. Year 11.

**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,646

That's a hard question to answer, Amy.

I think it has a lot to do with HOW you learn it.

I know myself that I can pick up some books, and can't even get half way through a page, whereas other books are easy to read on the SAME subject!

In other words, it may help you to look around for other ways to learn.

Maybe a different teacher at school, one who you understand well, could explain some things better. Or perhaps your parents could afford a tutor. Or just try a sample of different books from the library or bookstore.

And you could also go BACK to some of your earlier textbooks and try to figure out WHEN it first became really hard, there may have been some concepts you missed.

Because maths is all about building up concepts, and if you miss just one concept you can be in trouble.

When studying maths, you need to take it slow, and understand EACH STEP, and don't hesitate to ask questions. You will, after a while, start to understand it more clearly, and then you will want to do more and more and hopefully surprise yourself.

And don't hesitate to ask any specific questions here, ok?

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**onehelluvamathematician****Member**- Registered: 2005-02-16
- Posts: 1

Amy, just thought I'd give you a couple of tips on how to improve your maths. Maths is much more about doing than about reading. You could read a maths book for hours and not learn a thing. What you should do is find an example which you can understand and then do lots and lots of similar examples yourself until the method becomes extremely familiar. The biggest mistake that students make when studying maths is to give up once they encounter difficulties. They then avoid the subject in favour of other subjects and this only makes the problem worse. You have to put the time in to it and if you find yourself simply reading your maths book, take out a pencil and start working things out. If you find the problems difficult, go back to some simpler problems and work on these first. Good luck. If you get stuck on something, post a message and I'll see if I can help. By the way, I'm a maths teacher in Ireland.

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**nicestar_05****Member**- Registered: 2005-02-17
- Posts: 1

i have an important maths test coming u soon and i'm really bad at fractions, decimals and percentages. Any tips

*Last edited by nicestar_05 (2005-02-17 05:38:42)*

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,646

Well, we do have some simple explanations of fractions starting at Equivalent Fractions - look for the links at the bottom of the page for lots more about fractions.

Likewise you can check out Percentages and also do a short Percentage Test

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**Amber****Guest**

I have learnt that there is such thing as a reflex angle, which is over 180 degrees is this true?

**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,646

Correct, amber, and we have some examples of reflex angles here

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**Amber****Guest**

Thank you. I want to compliment you on this website, it is really helpful! Good job

**samantha****Member**- Registered: 2005-02-21
- Posts: 3

I need help!!

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**samantha****Member**- Registered: 2005-02-21
- Posts: 3

What is the equation of a graph that makes an M... The middle is on the origin and the sides approach negative infinity... help please

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,646

Well, by using the "absolute value" function abs(), you can use:

abs(x) - x^2 (absolute-value-of-x minus x-squared)

When I tried this on our graph plotter, I found it looked best using 2*abs(x)-x^2

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**j4tt****Member**- Registered: 2005-02-21
- Posts: 14

hi

i got a nice problem 4 you.

you got 12 numbers which are

1 1 1

3 3 3

5 5 5

7 7 7

how do you add any 6 numbers to make 21???

Remember no subtraction, division or multiplication and using only 6 numers not more not less..!!!!!!

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**samantha****Member**- Registered: 2005-02-21
- Posts: 3

Thats an M for sure... but i need it to be pointy like a captial M

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,646

Great puzzle, j4tt, but one little problem .... I can't figure it out!! Is there a trick?

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**amila123****Member**- Registered: 2005-02-22
- Posts: 1

I want to know about limits.=)

!!!Please HELP meeeeeeee!!!!!

*Last edited by amila123 (2005-02-22 19:34:10)*

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**j4tt****Member**- Registered: 2005-02-21
- Posts: 14

its simple problem.. but the solution is a bit hard to figure out.....

this is because by taking any odd number and adding it twice, thrice, 6 times or any number which is even you can get an odd number. i gave you 6 odd numbers and wanted 2 make it odd as well .....................HOW IS THAT POSSIBLE?????

so NO SOLUTION !!!!!!!!!!!!!!!

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,646

Well done, j4tt, of course it is impossible!

Well, amila123, "limits" just mean that if you keep going, where do you end up?

If you start walking fast, then get slower, and slower, and slower, eventually you will be able to figure out that you will never get beyond a certain point. That point is the limit.

It is best to see this by playing with graphs. Try going to these graphs, and choose "reciprocal".

As you move to the right, x increases, but y gets smaller. What if you move very far to the right? x approaches infinity, and y approaches 0. So, the limit at infinity is 0.

Now, that is just an easy example, and there is much more to learn, but the idea is still basically simple.

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**princess****Member**- Registered: 2005-04-11
- Posts: 12

I need to understand adding and subtracting negative numbers. For some reason this is confusing to me. Can you please help?

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,646

Hiya, princess.

Can be confusing !

The Number Line:

... -5 ... -4 ... -3 ... -2 ... -1 ... **0** ... +1 ... +2 ... +3 ... +4 ... +5 ...

Negative Numbers head to the left (this way **<--**), and positive to the right (this way **-->**)

If you have a positive number, say 3, you have this:

... -5 ... -4 ... -3 ... -2 ... -1 ... **0**>>>+1>>>+2>>>+3 ... +4 ... +5 ...

If you have a negative number, say -2 you have this:

... -5 ... -4 ... -3 ... -2<<<-1<<<**0** ... +1 ... +2 ... +3 ... +4 ... +5 ...

If you add them together you get this:

... -5 ... -4 ... -3 ... -2 ... -1 ... **0**>>>+1>>>+2>>>+3 ... +4 ... +5 ...

... -5 ... -4 ... -3 ... -2 ... -1 ... **0** ... +1<<<+2<<<+3 ... +4 ... +5 ...

In other words you go "3 paces to the right, then 2 paces to the left"

So, "negative" just means "go in the other direction"

Subtracting also means "go in the other direction"

So ADDING a NEGATIVE number is the same as SUBTRACTING a number

If you SUBTRACT a NEGATIVE number you have to "go in the other direction of the other direction", which turns you back to the normal direction again !!!

Have a look at Baby Steven coping with all of this in Multiplying Negatives

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