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Choosing a calculator (IGCSE)

Hi there,

Looking for some help choosing a calculator for IGCSE Maths. I recently bought a fx-991ES simply because of the feature of solving simultaneous equations and quadratic equations. Whilst it can solve the latter very easily, overall I find it quite complicated to use, e.g. it gives answers automatically in top heavy fractions, and you have to press another button to convert it to an integer. Another thing is that certain equations I put in, it comes up with a different result to my other calculator, something about brackets, but it just over complicates it. Another thing is, when doing trigonometry if I press "cos" , it will automatically come up with cos(...) , and I don't want the brackets, and don't know how to get rid of them!

So basically I want a normal calculator that can also do simultaneous equations and quadratics, and anything else extra useful for (i)GCSE Maths. My normal calculator is a Sharp EL-531W which is great but it doesn't do the extra stuff, and has stopped working anyway.

I won't be using the extra functions just to get the answers, more to check answers. Anyway, from the June 2008 exam (mine) they are more wary on calculators like that and are only giving the full marks when working is shown, before this was only on certain questions.

Thanks :smile:

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Reply 1
Avatar for Chewwy
Chewwy
17
why would you not want the brackets?
Reply 2
Avatar for m8nmina0h4
m8nmina0h4
OP
15
Chewwy
why would you not want the brackets?

Okay say I had the hypotenuse and angle B which is 25 degrees, and I wanted to work out the adjacent line. I would enter cos25x8 into my normal calculator, but into the Casio it comes up with cos(25x8)
Reply 3
Avatar for Chewwy
Chewwy
17
lol, just write the 8 first then. anyway, i don't know. 99% of students will just use a 'normal' calculator for gcse maths without simultaneous equations solving capabilities and all that.
Reply 4
Avatar for m8nmina0h4
m8nmina0h4
OP
15
Chewwy
lol, just write the 8 first then. anyway, i don't know. 99% of students will just use a 'normal' calculator for gcse maths without simultaneous equations solving capabilities and all that.

Okay fine but there's other stuff to too, like the answers coming up as fractions. Have to press two buttons to get Pie.. It's just annoying!
Reply 5
Avatar for Adjective
Adjective
12
If you really can't stand the fraction display of the fx-991es (personally I can't live without it!), there's no need to buy a new calculator to get rid of it. Simply press SHIFT, then MODE (which will now be SET-UP), then press the option for LineIO (which I think is option 1..) Now everything'll come out in decimals and stuff, like in older models of calculator.
Reply 6
Avatar for m8nmina0h4
m8nmina0h4
OP
15
Patent Pending
If you really can't stand the fraction display of the fx-991es (personally I can't live without it!), there's no need to buy a new calculator to get rid of it. Simply press SHIFT, then MODE (which will now be SET-UP), then press the option for LineIO (which I think is option 1..) Now everything'll come out in decimals and stuff, like in older models of calculator.

That's great, thank you ^repped, this is much better for me at GCSE!!!! Now say I want to keep it like that, but I want to do the any of the following:

Enter a fraction

Convert a decimal into fraction

Make a fraction appear in its simplest terms.

Do you know how I can do that, but leave it on the LineIO setting?

Thanks
Reply 7
Avatar for Adjective
Adjective
12
Entering a fraction: (numerator) [FRACTION BUTTON] (denominator)

Convert a decimal into a fraction: With the decimal displayed on the answer screen, press :undefined:.

Make a fraction appear in its simplest terms: Exactly the same as entering a fraction - then press =.

Hope this helps. :smile:
Reply 8
Avatar for m8nmina0h4
m8nmina0h4
OP
15
Thanks it helps, but they don't show up as graphical fractions if you get what I mean... is it only possible to have that on the other settings - if so bit let down :frown:

Do you know if this calculator can solve equations by any chance lol? I tried having a look at the manual but it is huge
Reply 9
Avatar for Adjective
Adjective
12
LineIO won't ever show fractions as ab \displaystyle \frac {a}{b} , I'm afraid.

It can solve equations - simultaneous equations with two or three unknowns, quadratics, and cubics. To access the solving mode, press MODE, then EQN (option 5). I think it's relatively self-explanatory from then on... but I urge you to read the manual!
Did you not reaq the manual. It is so easy to google for it and read it. That way you will actually know how to do everything without posting pointless posts here.

http://ftp.casio.co.jp/pub/world_manual/edu/en/fx-115ES_991ES_Eng.pdf
Reply 11
Avatar for m8nmina0h4
m8nmina0h4
OP
15
By any chance do you know if the calculator can convert a recurring number to fraction?

Thanks
KnightRider
By any chance do you know if the calculator can convert a recurring number to fraction?

Thanks

Yes - Yes it can
Press the S⇔DS \Leftrightarrow D button in LineIO mode and voila.
The great majority of the functions of this calculator can be discovered just by playing around with the buttons, figuring out the syntax, changing modes etc.

Try it - it's 'fun'.
Reply 15
Avatar for m8nmina0h4
m8nmina0h4
OP
15
sohanshah
Press the S⇔DS \Leftrightarrow D button in LineIO mode and voila.

Thanks this works for normal fractions, but say I have something like 0.23 recurring, if I enter say 0.2323232323 into the calculator nothing will have when I pres the SD button, probably because it doesn't recognise it as a recurring?

Any ideas?
You need to enter '23' a few more times before it'll recognise it as a recurring decimal, is all. You might want to try converting recurring decimals to fractions mentally, though :p:
KnightRider
Thanks this works for normal fractions, but say I have something like 0.23 recurring, if I enter say 0.2323232323 into the calculator nothing will have when I pres the SD button, probably because it doesn't recognise it as a recurring?

Any ideas?

Press 23232323232323232323232323232323232323232323232323232323 for about 15 seconds very quickly.

The calculator is too clever for its own good so it doesn't realise its repating yet.
Reply 18
Avatar for m8nmina0h4
m8nmina0h4
OP
15
Patent Pending
You need to enter '23' a few more times before it'll recognise it as a recurring decimal, is all. You might want to try converting recurring decimals to fractions mentally, though :p:

That worked, thanks :smile:

One thing not sure about though, the specification example of recurring decimals to fractions is 0.2333333333 (3 recurring) and the answer it gives is 21/90 ..

This is in the specification itself, so does that mean if I did actually work it out on the calculator which does gives the answer in simple terms I wouldn't get the mark?
KnightRider
That worked, thanks :smile:

One thing not sure about though, the specification example of recurring decimals to fractions is 0.2333333333 (3 recurring) and the answer it gives is 21/90 ..

This is in the specification itself, so does that mean if I did actually work it out on the calculator which does gives the answer in simple terms I wouldn't get the mark?

My calculator says 7/30.

If the spec says 21/90, its wrong. You should always cancel down.

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