First, your SUM() is superfluous - it returns the same value as

=A1*20

Next, to keep the 20 the same, just copy/drag the formula to the "next"
cell. XL doesn't update constants in formulae.

In article ,
"Confused" wrote:

How to you keep a number constant in a formula on the next cell?

Example:
Formula on line A5
=sum(A1*20)
and I want the 20 to remain the same in the formula on the next cell.