Looking for an easy shortcut on Excel (forgot what it is)?

I have to type numbers in Excel. A-H go all the way down to ten 8x10 grid), and in their columns are 10 of the same number. So in A it would be 1,1,1,1......(down to row 10) and in B it's 2,2,2,2,.....(row 10.) Last time I did this I used a shortcut that would automatically put all 1/2/3's in all 10 rows, rather than putting them all in manually. Can some one please tell me what that shortcut is because I have to go to like 1000.... Hopefully I explained that properly, i'll be checking the question often to see if any one has questions on what I mean.