To show the increase in another cell:
A1: 10
B1: =(1 + 10%) * A1 ===> 11
or a little more simply:
B1: =1.1*A1
To increase the value in-place:
Enter 1.1 in a blank cell. Copy the cell. Select the cell(s) to
increase by 10%. Choose Edit/Paste Special, selecting the Multiply and
Add radio buttons. Click OK.