Conversion / Impression
SUM([Conversions])/SUM([Impressions])

Conversion Rate
Sum([Conversions])/Sum([Clicks])

Cost / Conversion
Sum([Cost])/Sum([Conversions])

CPC Avg
Sum([Cost])/Sum([Clicks])

CTR
sum([Clicks])/sum([Impressions])

Position Avg
sum([Avg Position]*[Impressions])/sum([Impressions])


Complete Ad
[Headline]+" "+[Description Line 1]+" "+[Description Line 2]