Professional: I am the President of vCalc. vCalc makes free online calculators. vCalc is the place where people who understand how math is useful in any subject can build and share free online calculators. Of vCalc 12,000+ calculators, half were built buy our technical staff of professional scientists and engineers. The other half were built by partner universities that richly added to the collection of , , , , , , and calculators. vCalc also has a rich library of calculators to support the construction industry (, , , ). Expertise: I was educated as a mathematician and computer programmer, but have spent the bulk of my technical career as an aerospace engineer specializing in low Earth Orbit mission planning, real-time command and control and flight dynamics. ©