Is there a calculator with LaTeX-syntax?

Question

When I write math in LaTeX I often need to perform simple arithmetic on numbers in my LaTeX source, like 515.1544 + 454 = ???.

I usually copy-paste the

Answer 1

This is not exactly what you are asking for but it is a nice package that you can include in a LaTeX document to do all kind of operations including arithmetic, calculus and even vectors and matrices:

The package name is "calculator"

http://mirror.unl.edu/ctan/macros/latex/contrib/calculator/calculator.pdf