Relative cell referencing seems to make the most sense for the majority of worksheets. If you have to rearrange your worksheet, your relative cell reference updates as well. Absolute references are great when a formula points to a single cell, such as an age or pay value, that rarely changes. You could use dollar signs to anchor the cell reference in the formula that uses that cell but keep the other references relative in case you need to copy the formula around the worksheet.
What's the difference between the formatting you get by clicking the Center toolbar button and the formatting you get by clicking the Merge and Center button?
If you need to center the contents of one cell, both buttons perform the same task. If want to center data (such as a title) above a range of cell columns, however, select the range the centered cell is to go over and click Merge and Center; Excel completes the centering across the multiple columns .