Hello,
I was poking through Appendix E of the Calc info manual and found a small error in the documentation. The 'P' key (i.e. Shift+p) is described as producing an error form with '+/-'. For me this inserts pi, while lowercase 'p' triggers the '+/-' operation. Section 5.11 describes this properly.
Sorry I'm not taking advantage of M-x report-calc-bug. Email in Emacs is still foreign to me.
Hope this is useful.
- David