Conditional sum formula

Please be gentle, very novice smartsheet user!

I am trying to get a total value on a smart sheet when certain conditions are met.

I have a column called Type and a column called value, so when cell entries in column type are a particular value, I want a sum of the values recorded against that type in column value.  And I only want this between rows 2 and rows 18.  The formulas I've tried are:

=SUMIF(Type2:Type:18, Product, Value2:Value18)

=SUMIF(Type2:Type:18,"Product", ([Value2:Value18])

=SUMIF(Type2:Type:18,"Product"; [Value2:Value18])

But I just keep getting unparseable errors :-(

I've added a separate column to store the values in and set the column properties to number/text.

I'm sure its just a really rookie error but I can't figure it out for the life of me.