Hi all. I'm relatively inexperienced in Excel so apologies if this is simple and the solution is obvious, anyways... I'm setting up a basic sheet for a predict the match attendance competition on a football (English) forum. Scoring is basic, spot on =100 points, within 5=50, 10=25, 20=20, 30=15, 40=10, within 50=5, more than 50 away = big fat zero.

An example of 4 cells, C2 to C5...
C2 - The actual match attendance
C3 - Player's prediction
C4 - Difference between prediction and attendance
C5 - Score for that prediction based on the difference

so for C4 to always show a positive number for difference, and to only display a number if a prediction has been made I have entered
=IF(C3="",,ABS(C2-C3))

and in C5 to give the correct score when the attendance and prediction have been entered into C2 and C3 I have
=IF(C4<1,"100",IF(C4<6,"50",IF(C4<11,"25",IF(C4<21,"20",IF(C4<31,"15",IF(C4<41,"10",IF(C4<51,"5",IF(C4>50,"0"))))))))

This works when required data is entered into C2 and C3, but my issue is that when no prediction and attendance have been entered in C2 and C3, then C5 displays 100 for a spot on prediction because C4 is '0'.

So... How do I make it so that C5 only displays a score when a prediction has been made, as I have done with C4??? By trying to do the same as I have in C4 with =IF(C3="",, at the start it throws up an error.

Any help would be much appreciated, thanks