Among 15 consecutive natural numbers, the largest number is 3 times the smallest number. What is the sum of these 15 natural numbers?
15个连续的自然数中，最大数是最小数的3倍．这15个自然数的和是多少．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<gadget id="calculator">7 + 21</gadget>
<output>28</output>

<gadget id="calculator">28 * 7</gadget>
<output>196</output>

<gadget id="calculator">196 + 14</gadget>
<output>210</output>

<result>210</result>