In proportion, the product of two inner terms is the smallest prime number, one outer term is 4, and the other outer term is what.
在比例中，两个内项的积是最小的质数，一个外项是4，另一个外项是多少．
<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>