Am I crunching these numbers right?

[John Pope]

I am looking at buying my first property, and was just crunching some numbers for a high level estimate, and I see that i actually have a higher ROI if I buy with a mortgage and 20% downpayment than if i buy the property outright. How is this possible? Am i calculating correctly? I am calculating ROI as (downpayment + closing costs) / total annual profit.