The greatest common factor of 6 and a number is 3, and the least common multiple is 30. What is this number?
6和一个数的最大公因数是3，最小公倍数是30，这个数是多少．
<gadget id="calculator">30 / 6</gadget>
<output>5</output>

<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<result>15</result>