For example, here's what I'd do to the normal numpad to make it better:

There's no need for 2 u keys on it, IMO, so instead I'd add a =, comma and backspace key to it. Furthermore as most keyboards come with a nav cluster there' no need for a num lock button, so I'd swap that for a tab key. All these keys are very useful when you work a lot with numbers, and basically allows you to do number spreadsheets with JUST the nav and numpad. What do you guys think?