If I type in cell a1, for example, 450, and then push enter, is there a
keystroke that I can type that will put the same thing in the next cell.

In conclusion, in cell a1, I type 450 and then push enter which takes me to
cell a2,
is there a keystroke I can push that will put 450 in cell a2.

(Like in DOS, you hit the up arrow key, for the previous command) Any help
would be appreciated.