Hi- I tried that formula like this
(=sumA1*B1)
and like this
=sumA1*B1
.... and neither worked. If you want to multiply A1 times B1, then the
formula
=A1*B1 will do it.

There are circumstances in which adding the SUM formula into a
non-addition situation is useful, but (Warning! editorial content!) I
think it tends to be abused.

Please let us know if that last formula still does not work for you: we
may need to reset auto-calculation if it does not.

Cheers!