here's a website I used to use for that
http://www.meta-calculator.com/online/

Don't have one for offline use though.

>>138860
Matlab

Also when you have an internet connection there's nothing better than http://wolframalpha.com/
You could literally search for stuff like "population of america / population of the world" and it'll give you the actual answer, stats and everything.

There's also an wolfram app, even a cracked version that works perfectly.

>>138860
download wabbitemu and find a ti-84 + emulator. Both are free

desmos.com

You could try Matlab, Mathematica or Maple.

None of them are free. Matlab offers a free trial for a month if you're interested in it. I believe Maple is cheapest one.

If you don't want to drop your shekels, you could easily find a cracked version of any.