|Google something like Excel Command Button for lots of hits on how to create a Command Button and assign a macro to it.|
This is just one of many sites: http://www.mrexcel.com/tip068.shtml
As far as the code required, your question isn't clear.
I understand the part about reducing the values in the selected cells by 10% and I'll provide code for that below.
However, this part is not clear:
a similar button that also adds 10 or 2
Do you mean 10 or 2 percent or the actual value 10 or 2?
Do you want the code to randomly decide whether to add 10 or 2?
Do you want to be able to choose the value that is added after you click the button?
Do you a button specifically assigned to adding 10 and another button specifically assigned to adding 2?
Note: The following code checks to see that the value in each selected cell is a number. If it is, it reduces it by 10%, if not, it skips it. However, if the value is the result of a formula, it will replace the formula with the value minus 10% and the formula will be lost. You can't subtract 10% from a formula generated value and retain the formula since the formula would no longer be accurate.
If you study this code and understand how it works, you should be able to modify it to add your 10 or 2.
'Loop through selected cells
For Each myCell In Selection
'Check to make sure cell contains a number
If IsNumeric(myCell) Then
myCell.Value = myCell - myCell * 0.01
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