Why ?

When I needed to do a calculation, I was allways disappointed with the simple calculators and found the spreadsheets to be too heavy and complex for my needs.
powerCalc is beetween them

pro calc :easy to run
lightweight
free

cons calc: keyboard useless
can't save/share
no variables
can't re-run calculation with different values
no mathematical functions

pro spreadsheet :can save/share
variables
can re-run calculation with different values
mathematical functions
not free

cons spreadsheet: difficult to run
heavy
cannot edit easily saved calculations
nothing exist to share calculation or to build a library

easy to run
lightweight
can save/share
variables
can re-run calculation with different values
mathematical functions
edit easily saved calculations
share calculation or to build a library
free