You can do all sorts of neat things with Excel, such as computing the nearest E12 value. Select the cell under ‘Input’ and enter the value that you want to have rounded off. Type the value with all necessary zeros, thus ‘6800’ instead of ‘6k8’ and ‘1200000’ instead of ‘1M2’. The nearest E12 value will appear in the cell just to the right. It’s handy to permanently install this program on your computer, so that it’s always available when you need it.