Calc-table-#name

Hello!
When I tried to write certain formula into calc cell,
=c2³-NN

(NN is the name of other cell containing number), I got #name .
When I wrote the same formula without cubing it:

=c2-NN

then it went right.

But,
I wanted c2³, not c2!!!

Please, can someone help?
Many thanks!!!

Try

=C2*C2*C2-NN

or

=C2^3-NN