Not sure how to lookup and match.

Sheet1 has following data.

Inv# amount Principal Interest
20280828 411,396.52 ?
20280830 (316,035.60) ? ?

Sheet2 has following data.

CM# DM# Ppal Int
20280828 411,396.52
20280830 (300,000.00) (16,035.60)

I would like to fill the "?" mark based on Inv# lookup/match in sheet2.

Thanks.

Dinesh