Need Help Calculating CAP Rate!

[Fred Watson]

I'm currently analyzing a 10 unit small apartment property whose P & L has missing rents from various tenants all throughout the year. This is causing the income to be very low for a 10 unit. The NOI is $12,407 and the list price is $415,000. After I calculate NOI divided by the price, I get a CAP rate of 3%. This seems very strange, so can anyone tell me if I did my math correctly or if I should use a different formula? Thanks for the help!