How do I use the decimal tab on my computer in excel 2007??
What's a decimal tab?

In MS-Word, a decimal tab lines up the decimal points in a column of
numbers, even if some have more decimal places than others; for example:
123.8
3.678
22.

One way to simulate this is to use the TEXT function with the format_text
parameter depending on how many decimal places the number has. This works
with fixed-width fonts (like Courier) when the result is right-justified in
the cell.

The following works for up to four decimal places. For more places, it
should be clear how to lengthen the format_text (the second parameter of
the TEXT function).

=TEXT(A1,
IF(MOD(1000*A1,1)=0,
IF(MOD(100*A1,1)=0,
IF(MOD(10*A1,1)=0,
IF(MOD(A1,1)=0,
"0. ","0.0 "),"0.00 "),"0.000 "),"0.0000"))