The greatest common divisor of two numbers is 6, and the least common multiple is 420. If the difference between these two numbers is 18, what is the smaller number?
两个数的最大公约数是6，最小公倍数是420，如果这两个数相差18，那么较小的数是多少？
<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<result>12</result>