I searched the forum and didn't find anything on this, I'm sure this undocumented trick is known, butI can't find whee it has been shared.....
It has really bugged me that there was noway to lock the Num key so you could easily enter a series of numbers without having to physically hold down the Num key. Today I figured out how.
If you press Shift and then Num, the keyboard ewill lock the Num key down until you repeat the same key sequence. Unfortunately, if you want to enter a normal key during your string of numbers while Num is locked you can't simply press Shift and the normal key (like if you need to backspace over a typo).
You have to Shift Num to release the lock and then use the standard keys, then Shift Num to once again lock the Num key.
I find this quite useful when editing a spreadsheet!