User Variable

Is there a way that the user can interactively use variables constants from the command line?

What I would like: the way that variable speedcrunch is handled, in that you could type:
When specifying a line length, you could type thickness+5.5.

ans, would be a handy thing, that returns the last answer.

You could also use to store things like the weight of steel for volume calculations, such as:

If you get board, check out Speedcrunch. What makes it useful, is that all the user variables are saved/loaded when the program is closed, and you can get a list of variables.

I am sorry that their website is so useless, but…

Yes, this is also one of my oldest wishes …
I hope it’s already in the list.