The fill handle - numbers
The fill handle is a convenient tool in Excel that lets you quickly carry over cell contents throughout each sheet. Simply look for the black square at the bottom right of any cell, and click and drag it either horizontally or vertically depending on your needs (the fill can be conducted in any of the four directions of the spreadsheet).
If you drag a single cell, the contents of that cell will be duplicated across every cell you fill.
If you drag multiple cells with a distinct pattern, the pattern will be continued automatically in your fill.
For instance, if you create a cell with the number “1” in it, and a “2” immediately below it, and fill in the pattern for 8 cells beneath the 2, your cells will count upwards to 10.