uCalc

Current scientific calculators only do half the job, they calculate the numbers whilst leaving  out the units.  Keylink’s calculator does both and it does it in a very easy to use intuitive way.  The above calculation for the force on a 10kg mass at the Earth’s surface is simply calculated by using the usual keystrokes with a few extra to specify the units.   

This is what makes this such a powerful tool for science.  Any mistakes are made obvious by the units.