There are 100 runners in a marathon race. Give them number cloths from 1 to 100, how many athletes have the number 7 on the number cloth.
马拉松长跑比赛中有100个运动员．分别给他们1～100的号码布，号码布上有数字7的运动员有多少名．
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">10 + 9</gadget>
<output>19</output>

<result>19</result>