The temptation will be to use this:
=IF(OR(SUM(A1:A15)=23,SUM(A1:A15)=24,SUM(A1:A15)=25,SUM(A1:A15)=26,SUM(A1:A15)=27),TRUE,FALSE)
...but, as you can see is evalutes the sum of your
range repeatedly, and; therefore, is inefficient!
Instead, consider using one of these...
...an array formula as a solution:
{=IF(OR(SUM(A1:A15)={23,24,25,26,27}),TRUE,FALSE)}
Note: Array formulas are entered using the
Control+Shift+Enter key combination. The outermost
braces, {}, are not entered by you -- they're
supplied by Excel in recognition of a properly
entered array formula.
...or a non-array formula:
=IF(PRODUCT({23,27}-SUM(A1:A15))<=0,TRUE,FALSE)
=IF(AND(A1>=23,A1<=27),"ThisSymbol","ThatSymbol")
where A1 contains a SUM formula of those "15 cells" you mention.
Given the structure of the numbers {23,24,25,26,27}, it's better to map the problem on AND rather than on OR.
Aladin
Aladin