I do search and not see this before, so I am looking for clarification. I have to do a permutation this morning and when I look on page 4-15 of 35s manual, it is my understanding that to find a permutation, I must type N (number of items) first, then press nPr and then r (number of items at a time). If I follow this instruction, I get INVALID DATA message.

Am I correct in thinking that I must enter n into calculator and hit ENTER, then enter r and press nPr? This seem to give correct result. Did I misread manual?

*Edited: 28 Aug 2007, 10:16 a.m. *