I have this in my criteria but it doesn't work? CASE WHEN {number} ="1680" THEN 1 ELSE 0 END

I'm not an expert but I feel like there should be a DECODE statement in there for the transaction id?

Change the double quotation marks to single. '1680' instead of "1680". Use Formula (Numeric). If it's a summary search do use your criteria as a Summary criteria if that applies.