The sum of 7 consecutive natural numbers is 63, what is the smallest natural number among them?
7个连续自然数的和是63，其中最小的自然数是多少．
<gadget id="calculator">63 / 7</gadget>
<output>9</output>

<gadget id="calculator">9 - 3</gadget>
<output>6</output>

<result>6</result>