How many twelfths equal three-sixths? We set up the equation below where x is the number of twelfths in three-sixths: 1/12x = 3/6 Cross multiply, and we get: 12x * 3 = 6 * 1 36x = 6 To solve for x, we type this in our math engine and we get: x = 1/6 or 0.16667