Syntax to set set cells to be zero
 

Actually i have created a button for retreiving teh data (numerical
figure) from one worksheet to another worksheet but that requires some
addition and subtraction on the original value. I now would like to
make every "to be filled cells" to be "zero" which can help me to do
the subtraction later on. So I wonder if there is anyone can teach me
some the syntax for that operation. ( i would like to make a button to
set those cells zero first) Anyone please help!