Alison it great to see XLC being used in schools so thanks for the question. XLC will not rename the Excel's Fact() function but here is a work around. Name a cell manually "n!=" (note if the cell is named "n! =" it will be automatically subscripted which is XLC's default behaviour - omitting the 'space' before the "=" allows you to format an name any way you like - then the name is dragged into equations). This is covered in the online help just below the flash tutorial. http://www.excelcalcs.com/content/view/52/126/

I have amended and attached your calculation. I have also taken a stab at formatting nCr - but I am not totally sure what you want to achieve her. This should keep you going - keep on opening the miraculous world of maths to our young people!