How do I input a 5-digit number into Excel so that they are in separate boxes
on the same line, but I don't have to press "Tab" each time to move to the
next box?

For example what I have right now is the number 53421, with subnumber "5" in
the first cell, subnumber "3" in the second cell, etc. Each time I enter one
of these 5-digit numbers I have to hit tab after each subnumber--which means
hitting tab 5 times for each number. This is a bit inconvenient when
entering many numbers.

It doesn't matter to me if this number is all in the same cell or different
cells. But I want to keep the gridlines so that each subnumber is in it's
own box on the same line. This should be really simple, but I can't figure
it out. Any ideas? Thanks.