I have a worksheet called 'Pay Details' which I am referencing from another worksheet in the same Workbook. I entered ='Pay Details'!A3 in a cell in the other sheet but instead of the data from the target cell it shows ='Pay Details'!A3
Perhaps this cell is in text format. If so, apply General and re-enter formula (F2, Enter). In addition please check on ribbon if Formulas->Show Formulas is OFF
