Maths Paper 2 significant figures

[burndtjamb]

I'm a bit confused about the number of significant figures we should include in our answer... I know they say 3 significant figures on the paper but in May/June 2010 paper 41 the answer for question 11) d) ii) is to 5 significant figures (20202) and they do not tell you to use this amount of significant figures. How are we supposed to know?

 

[ChrisChin]

Erm... The number of significant figures only applies to decimal values. 20202 is an integer. You're not supposed to round 20202 to 20200...

 

[cooldude100]

use 3 significant figures or 1 decimal place for your answer...

 

[ni00142]

The question was to solve a sequence formula and so You had to give the exaxct number of dots that was present

 

[Ramosk95]

no you should write 3 s.f but how to know if they want more s.f look at your calculator if it has three decimal places maximum then you should write all of the numbers down.ex: 750.25 on your calc. write all the fugures that ur calc. display . now for large no. such as 7559.25547378 u should write down 7560.

 

[ChrisChin]

... D:

@ cooldude, your answer is a blanket statement. Special conditions exist where the rule does not apply, for example this case. This particular question clearly requests for a whole number -- a fraction of a dot is still a dot. Neither can you correctly round off to 3sf, because then you will be 2 dots shy of a complete sequence. If you can give an accurate answer, give it instead of rounding. We only use rounding when there are more than a few numbers following the decimal place.

@ ramosk, although your answer is more correct, there are times when the rule you follow does not apply. 7559.25547378 in some cases would be either 7559 or 7560 if you're dealing with discrete values. The question will tell you which number you should use as the answer.

For that particular question, and all other questions, where the answer is supposed to be a whole number, DO NOT ROUND TO 3SF.

Let me repeat -- rounding to 3sf or otherwise is only for fractions and decimals.

Depending on the purpose, the number of people at your birthday party that is equal to 33% of the number of your acquaintances is a whole number. We don't expect an arm to show up without the rest of the person, so either the rest of the person tags along or not at all. The answer is 20202 dots, if your answer is 2 less than that, then your sequence/diagram is incomplete.

The short answer is, if you are dealing with discrete values, the 3sf guide does not apply.

 

[Ashique]

I'm sorry to be dumping an old thread. But I wrote my answer in the working space, the CORRECT answer that is.. And I was confused about the s.f too.. so I changed it.. Will I lose marks? The answer is clearly shown in the working. Below it I wrote
3 s.f= this and that.

I really hope I dont lose anything.

 

[ChrisChin]

Er... I'm a little confused as to what you meant... I'm guessing your answer in the working space is correct, but the final answer you gave in the space provided for it is different? If so,

The examiner will take the final answer, rather than the one in the working space. We treat it as a mistake you made in transferring the answer -- and it DOES cost you 1 mark. You will be awarded the other marks, provided of course the working is correct and complete up to that point.