I am trying to write a formulae that returns an A, B, C or D depending on
percentage scored in a test.
i.e i will have students who do a test, then receive a percentage mark out
of 100.
Then i would like to convert that to a grade as below.

Say 0 - 50 = D
51 - 69 = C
70 - 85 = B
86 - 100 = A

Can anyone help please. I have succeded in doing this in a lookup table but
I would like to be able to write this in a single cell as a formulae. I have
tried doing it with an IF statement but can't seem to get my head around it.

Thanks in advance ....