The property tax is the annual tax. This number was figured using a mill rate of 16.98 in Worcester, MA. A mill rate is 1/10th of 1 cent. So, for every thousand the property is accessed at, 1 mill = 1 dollar in taxes. An easy way to calculate this is to put a decimal where the comma is in the accessed price of the property. This property was accessed at $73,100 in 2012. So to figure out the taxes we would input 73.1 x 16.98 into the calculator which gives us $1241.24....Trulia rounded down.
Now for the mortgage payment. I'm trying to figure out where you've figured $67 per month. Chase bank (Trulia estimate at the top) is figuring $447 per month after 20% down. Let me know how you figured $67 per month and I'll figure out where you went wrong.