Numeric Entry
=============

Pressing a digit or other numeric key begins numeric entry using the
minibuffer.  The number is pushed on the stack when you press the RET
or SPC keys.  If you press any other non-numeric key, the number is
pushed onto the stack and the appropriate operation is performed.  If
you press a numeric key which is not valid, the key is ignored.

There are three different concepts corresponding to the word "minus,"
typified by `a-b' (subtraction), `-x' (change-sign), and `-5'
(negative number).  Calc uses three different keys for these
operations, respectively: `-', `n', and `_' (the underscore).  The `-'
key subtracts the two numbers on the top of the stack.  The `n' key
changes the sign of the number on the top of the stack or the number
currently being entered.  The `_' key begins entry of a negative
number or changes the sign of the number currently being entered.  The
following sequences all enter the number -5 onto the stack: `0 RET 5
-', `5 n RET', `5 RET n', `_ 5 RET', `5 _ RET'.

Some other keys are active during numeric entry, such as `#' for
non-decimal numbers, `:' for fractions, and `@' for HMS forms.  These
notations are described later in this manual with the corresponding
data types.  See Data Types.

During numeric entry, the only editing key available is `DEL'.