=IF(C12="B",-J12,IF(C12="S",J12,NA()))

What happens if C12 is neither B or S?

Ed Ferrero

I am trying to get a cell to render a positive value or a negative value of
a
certain number if another cell has one of two letters. i.e.:

if the value of cell J12 = .28 and the first letter of cell C12 is B, then
the value of cell K12 = (0.28).

if the value of cell J12 = .28 and the first letter of cell C12 is S, then
the value of cell K12 = 0.28.

I am stuck. Can someone shed some light?

eric