It is known that the greatest common divisor of two numbers A and B is 6, the least common multiple is 84, A=42, B=how many.
已知A、B两数的最大公约数是6，最小公倍数是84，A=42，B=多少．
<gadget id="calculator">84 / 42</gadget>
<output>2</output>

<gadget id="calculator">2 * 6</gadget>
<output>12</output>

<result>12</result>