The six faces of a square are marked with 1, 2, 3, 3, 5, 6 respectively. What is the probability that the prime number will go up when the square is thrown?
一个正方形的六个面上分别标有1、2、3、3、5、6，把正方形掷出去，质数向上的可能性是多少．
<gadget id="calculator">4 / 6</gadget>
<output>2/3 = around 0.666667</output>

<result>2/3 = around 0.666667</result>