The greatest common factor of two numbers A and B is 4, the least common multiple is 60, A is 12, what is B.
甲、乙两数的最大公因数是4，最小公倍数是60，甲是12，乙是多少．
<gadget id="calculator">60 / 12</gadget>
<output>5</output>

<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<result>20</result>