Because if you don’t show your working out, then it’s not obvious how you got the answer. There’s no actual proof that you knew how to get the right answer.
I say this to my students who ask why do they have to show working out:
- “You might not know how to work out the answer so you guessed it and guessed it right – Good guess!”
- “You might have copied from someone else who did know how to work it out.”
- “You might actually know how to work it out without showing steps – great!.”
“If I can’t see how you got your answers then I don’t really know how you got them.”
And I would also add:
“If you don’t show your working out then I’ll only give you one mark if you get the right answer. If there’s no working out then you won’t get full marks even if your answer’s correct.”
Once my students realised that they needed to show working out to get the marks, they showed their working out.
Teachers have to know that you’ve done the work yourself and the only way they know for sure is if you show your working out.
Why do you think you shouldn’t have to show your working out?