Fractions and M1

Hi!

I was wondering whether or not Edexcel are okay with us giving fractions instead of whole numbers in M1 (assuming it does not ask for the figure to a certain number of significant figures). Looking at the mark scheme, they do not give the answers in fractions, but it would make sense if they accepted fractions because they're more accurate.

Just wanted to make sure I knew before the exam on Wednesday, and any input would be much appreciated.

Reply 1

Zacken

Original post by Jasaron

You can give your answer in exact form or fractions as long as you do not make use of any approximations during the calculation. This includes approximating

g

as 9.8 metres per second per second.

(edited 7 years ago)

Reply 2

username1628823

Original post by Zacken

You can give your answer in exact form or fractions as long as you do not make use of any approximations during the calculation. This includes approximating

g

as 9.8 metres per second.

You've probably saved me a few marks on Wednesday! I'm probably better off sticking to 2-3sf, then. Thank you.

No worries.

Original post by Jasaron

You've probably saved me a few marks on Wednesday! I'm probably better off sticking to 2-3sf, then. Thank you.

On a related note, last year there was a lift question where so many people lost a mark for writing 2043 as their answer. But since g was used in the working 2043 must be rounded to 2sf or 3sf.

Even Arsey's model answers had a rounding mistake.

(edited 7 years ago)

Reply 5

username1628823

Original post by notnek

Wow, that's quite harsh. They should have a notice on the front of the paper telling students that they should keep to 2sf. It makes sense, though. Thanks for letting me know, you've probably saved me a few marks on Wednesday.

Reply 6

Zacken

Original post by Jasaron

They have on recent papers:

Reply 7

username1628823

Original post by Zacken

PRSOM

Never read the front of a maths paper in my life, and I doubt many other students do. That being said, it's not the exam board fault, and it makes sense having to present our answers like that if we use a simplified figure in our workings.

Reply 8

tiny hobbit

Original post by Jasaron

I would claim that it is your teacher's job to make you aware of this. It gets mentioned in the examiner's report for nearly every Edexcel Mechanics paper.

Reply 9

Zacken

Original post by Jasaron

Yeah, it not only makes sense but it's requisite scientific practice. I can't say something like

"okay, I'm going to say the radius of the earth is R = 10,000 kilometres to the nearest ten thousand even though it's 6400 km to 2 s.f, and using that I get the mass of the earth to be 2.3838383234234 * 10^28". No ways, my final answer is guaranteeing that much accuracy even though I made a massive simplification earlier on? Not having it. If you use an approximation earlier on, your final answer should be stated to that same approximation.

Reply 10

username1628823

Original post by tiny hobbit

I would claim that it is your teacher's job to make you aware of this. It gets mentioned in the examiner's report for nearly every Edexcel Mechanics paper.

Not knowing certain things pertaining to exams is something that comes with going to an under-performing state comp. It's a good thing I have TSR to clear these things up!