more keys on a keyboard (revised for mathematics and number-entry)
i've explored a similar topic before, but this time i'm focusing on mathematics and possibly other areas such as financials and economics with this idea.
basically it's multiple numeric keyboards that focus on each of the ones, tens, hundreds, and thousands.
numeric keyboards can be purchased for about roughly $12 (U.S.) or perhaps even cheaper if you do your shopping.
instead of focusing on making keyboards smaller, why not make them bigger?
if the keyboard was in a desktop environment, and the keyboard was bigger (including more keys) then this can greatly increase the efficiency of data-entry.
a cheap way to do this would be to purchase multiple numeric keypads (commonly referred to as numpads) and let the software (the idea) determine which keypad is being used and input the numbers appropriately.
for instance, to insert the number three hundred and twelve into a spreadsheet, you could actually type the number 1 on the middle keypad, then type the number 3 on the left keypad, then type the number 2 on the right keypad, considering there is only 3 keypads available. this would result in the number 312 being inserted.
if one realises that a mistake was made on the middle keypad and it shows up in the spreadsheet as 362 instead of 312, all you would have to do is press the middle keypad once, typing the number 1 to over-write the middle character, which in effect withdraws the need to press backspace twice, type 1, then type 2, then check again to see if the correct input has been fed into the spreadsheet. instead it would over-write the 6 in the tens column with the 1.
now, pressing backspace twice and re-inputting the numbers may not sound like much over-head, but when dealing with huge amounts of data, this could save much needed time when it comes to dealing with such amounts of data-entry.