Taxes are determined by the assessed value of the property. Once the property has been assessed by an appraiser for the county and/or township, an equation is used to determine the taxes. The number the townships use to multiply the property assessed value by is called the millage. Each township has a different millage. So... it's the properties value x the township millage multiplier.
Example: If the properties value is $100,000 and the township millage is .1, then...
$100,000 x 0.1 = $1,000
Hope this helps!