The sum of two consecutive natural numbers is 21, what is the least common multiple of these two numbers.
两个连续自然数的和是21，这两个数的最小公倍数是多少．
<gadget id="calculator">21 - 1</gadget>
<output>20</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">21 + 1</gadget>
<output>22</output>

<gadget id="calculator">22 / 2</gadget>
<output>11</output>

<gadget id="calculator">10 * 11</gadget>
<output>110</output>

<result>110</result>