Maths teachers - can you give me some advice on marking A’level papers for DS?

[tomorrowyoullknow]

DS has been doing A’level past papers and I’ve been trying to mark them. He’s getting the answers right but sometimes the method he gets there is quite different to the ones used on the mark scheme. Does this matter? His board is Edexcel.

Not a maths teacher.
Doesn't the mark scheme say "or equivalent method" or some such dislaimer?
If he gets the right answer, I'd say he's doing it right and so gets the marks.

No I don’t think it does.
It’s incredibly complicated. I’m rubbish at maths though!

Can you post an example here OP?

Some examples:

I’m the red pen but no idea if I’ve marked it right or not.

I'm a former Maths teacher (and helped my DS with A level last year), and the answers look pretty much by the book to me, so I'm surprised if they are that different from the mark scheme.

Q2 looks absolutely fine.

Q7b - only comment might be to say why that answer means it is inv. prop. ("of form constant / k").

Q5 - I didn't check every line, but obviously doing the right thing and if the final line agrees the mark scheme then I am sure he's doing it right.