It needs to be more functionality such as scientific and programmers calculator

[nazares]

It is not so cool to be the default calculator for the whole OS with that poor functionality. I would say nothing if it would be another one kid's handmade calculator. But you position this as the default tool for ElementaryOS.

[jeremypw]

That may be so, but we need a list of specific features, preferably prioritised, so that issues can be raised against each. Calculator provides most of the basic mathematical functions like arithmetic, trigonometric and logarithmic as well as memory and parentheses. Some are hidden behind the extended functionality button.