When trying to add an element to my report to contain a function/formula to run at runtime in either a 'textbox' or 'formatted field':
ADD TEXTBOX or FORMATTED FIELD to report in design view:
Right click on the object - control - data - datafield (greyed out)
using for a GCSE exam and students are unable to add runtime formulas as requested in exam papers so this is really urgent i can find a work around!!!

Let me know if there is further info which needs adding, i have spent hours trying to find a work around!