# The basis of RPN - *Chapter 2*

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## Notes about negative value in RPN-Enh

in RPN-enh, when entering negative values for matrix, lists or complex, you can type directly value with the minus sign.

ex : `[ 1 -1 -1]`

or `{-1 -2 -3}`

or `(-1;0)`

the reason is simple, the calculator knows you are not working with stack because you start working with matrix/lists.. you first hit `[`

or `{`

or `(`

, in this way when you hit `-`

system does not try to compute a substraction.

__example__,

hit `(`

key, a specific entry screen appears :

now type -1, you can now move your cusor to the right to enter 1, you can see that you have now `(-1;1)`

, press the enter key, you've just created a complex number (-1;1).

There are no trouble to enter negative values in matrix/complexes/lists.

If you want to enter negative value for numbers which are **not** in matrix/lists or complexe number, you have to use **NEG** command.

Because if you try to hit `-`

key, the system will interpret it as a substraction.