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An alternative to using the
ANS
key is to use the History facility and the
function. This is discussed on page 43.
The negative key
Another important key is the
(-)
key (shown right).
If you want to calculate the value of (say)
2 ( 9)
− − −
then
you must use the
(-)
key before the 2 and the 9 rather than the subtract
key. If you press the subtract key before the 2 instead of the
(-)
key, then
the calculator will enter instead:
Ans - 2
, meaning, subtract 2 from the
previous answer. Similarly, entering ‘subtract, subtract 9’ instead of ‘subtract
(-) 9’ will give an error message of “Invalid syntax”, meaning it does not make
mathematical sense to have two subtract signs instead of a subtract of a
negative.
The reason for the
Ans - 2
is that a subtract cannot start a ‘sentence’ in
mathematics, while a negative sign can. Since the subtract can’t come first,
the calculator decides that you must have intended to subtract from the
previous answer. Hence the sudden appearance of an
Ans
. This occurs at
other times too. One of the most common
The
CHARS
key
The next important key is the
CHARS
key (above
VARS
). This key is used to
access all of the many characters that are used occasionally but not often
enough to bother putting on the keyboard.
Pressing
SHIFT
CHARS
will pop up the screen
above right. One of the screen keys is set to
be a ‘Page Down’ key (
), and will give
access to two more pages of characters.
These special characters are obtained by
pressing the screen key labeled
. You
can press
as many times as you need to
in order to obtain multiple characters. When
you have as many as you need, press the
key.
