I'm an IGCSE Maths Teacher - Post your questions here.

[aaaamfa]

need help in the following question:
0580/41/m/j/10:
question no. 10d

 

[inquisitiveness]

CIE has strict rules regarding rounding:

If the answer has less digits than the full calculator display, write down all the digits you see (this kind of number is called 'exact'). If you round your answer, you'll lose marks.

If the answer is not 'exact', round to 3sf and for angles round to 1dp. Sometimes the question will ask you to round to something else so read the question carefully.

Finally, always remember to only round your answer (if it is not exact). If you use rounded answers from previous questions in your working, you will lose marks.

can you please give me an example when the answer is not exact and when it is exact so that i can understand clearly what you just said....

 

[ZaqZainab]

http://papers.xtremepapers.com/CIE/Cambridge%20IGCSE/Mathematics%20(0580)/0580_s12_qp_43.pdfquestion 6 d ii

 

[Noorullah Farid]

can you explain me june 2000 question 8ci ? thanks

 

[Majd Aldeen]

You can use it for any question if you need it.

It's mainly useful for drawing or describing rotations. It is also useful for some loci questions where you are asked to draw the locus of a point as it moves (this kind of question is pretty rare).

still i cant get it
can u give me an example

I will be thankful sir....

 

[notnek01]

can you please give me an example when the answer is not exact and when it is exact so that i can understand clearly what you just said....

Sure. E.g. a question contains this multiplication:

6.153*3.253 = 20.015709

This number fits completely on the calculator screen so you know that 20.015709 is the exact number.

For this exact number, write all of the digits you see in the answer space (unless the question tells you something else).


E.g. A question contains this:

3*sqrt(6) = 7.348469228

These are the only digits you see on the calculator because there is not enough room. The actual number is an infinite decimal (because it is irrational). So 7.348469228 is not the exact number. For non-exact numbers like this, round to 3sf or 1dp if it's an angle.

 

[Ebby_SaLeem]

Sir I need help in Probability.
In October/November 2007 Paper 4 (http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_w07_qp_4.pdf)
Question 2 (a) (vi) I have no idea at all how to do this! Please help!

 

[notnek01]

http://papers.xtremepapers.com/CIE/Cambridge%20IGCSE/Mathematics%20(0580)/0580_s12_qp_43.pdfquestion 6 d ii

Two choices: Either (1st person on holiday, 2nd person not on holiday) or (1st person not on holiday, 2nd person on holiday).

Once you choose a person, they can't be picked again so this is a 'without replacement' question.

P(1st person on holiday, 2nd person not on holiday) = 180/240 * 60/239

P(1st person not on holiday, 2nd person on holiday) = 60/240 * 180/239

Add the two probabilities together to get the answer.

 

[notnek01]

can you explain me june 2000 question 8ci ? thanks

Do you have a link to this paper? The current computer I'm using does not have the papers for 2000.

 

[notnek01]

still i cant get it
can u give me an example

I will be thankful sir....

I can't show you how to use tracing paper on an internet forum. You should ask your teacher to demonstrate.

 

[Noorullah Farid]

Do you have a link to this paper? The current computer I'm using does not have the papers for 2000.

i downloaded it from freeexampapers

 

[ZaqZainab]

http://papers.xtremepapers.com/CIE/Cambridge%20IGCSE/Mathematics%20(0580)/0580_s12_qp_43.pdfQuestion 9 b

 

[Noorullah Farid]

Do you have a link to this paper? The current computer I'm using does not have the papers for 2000.

 

[notnek01]

Sir I need help in Probability.
In October/November 2007 Paper 4 (http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_w07_qp_4.pdf)
Question 2 (a) (vi) I have no idea at all how to do this! Please help!

If this does not happen until the third pick then it means that for the first two picks, the student chosen does not have a grade 5.

= P(1st student chosen does not have grade 5) * P(2nd student chosen does not have grade 5)* P(3rd student chosen does have grade 5)

= 24/28 * 23/27 * 4/26

 

[Ebby_SaLeem]

If this does not happen until the third pick then it means that for the first two picks, the student chosen does not have a grade 5.

= P(1st student chosen does not have grade 5) * P(2nd student chosen does not have grade 5)* P(3rd student chosen does have grade 5)

= 24/28 * 23/27 * 4/26

Thanks a lot! I finally got it!
I wish mark schemes were like that :/

 

[notnek01]

http://papers.xtremepapers.com/CIE/Cambridge%20IGCSE/Mathematics%20(0580)/0580_s12_qp_43.pdfQuestion 9 b

fg(x) = f(g(x)) = f(1/x) = 1 - 2(1/x)

= 1 - 2/x = x/x - 2/x = (x-2)/x

 

[inquisitiveness]

Sure. E.g. a question contains this multiplication:

6.153*3.253 = 20.015709

This number fits completely on the calculator screen so you know that 20.015709 is the exact number.

For this exact number, write all of the digits you see in the answer space (unless the question tells you something else).


E.g. A question contains this:

3*sqrt(6) = 7.348469228

These are the only digits you see on the calculator because there is not enough room. The actual number is an infinite decimal (because it is irrational). So 7.348469228 is not the exact number. For non-exact numbers like this, round to 3sf or 1dp if it's an angle.

wow I never knew this,thank you so so much!!!
if they say Pablo plants x lemon trees and y orange trees.
(a) (i) He plants at least 4 lemon trees.
Write down an inequality in x to show this information
why cant we write x >= 4 as they are saying ATLEAST which means equal or greater than right?the answer was x>4 without the equal to sign..

 

[notnek01]

Thanks a lot! I finally got it!
I wish mark schemes were like that :/

If CIE paid me, I'd make mark schemes with explanations for every paper

 

[ZaqZainab]

Two choices: Either (1st person on holiday, 2nd person not on holiday) or (1st person not on holiday, 2nd person on holiday).

Once you choose a person, they can't be picked again so this is a 'without replacement' question.

P(1st person on holiday, 2nd person not on holiday) = 180/240 * 60/239

P(1st person not on holiday, 2nd person on holiday) = 60/240 * 180/239

Add the two probabilities together to get the answer.

okay thanks

 

[Noorullah Farid]

If CIE paid me, I'd make mark schemes with explanations for every paper

i atached june2000 p4 above can u plz explain 8ci