In the shooting competition, Xiao Li made 8 shots and scored 18 points in total, and there were only 2-pointers and 3-pointers, how many 3-pointers did he make?
投篮比赛中小李投中了8次共得18分，只有2分球和3分球，则他投中的3分球有多少个．
<gadget id="calculator">2 * 8</gadget>
<output>16</output>

<gadget id="calculator">18 - 16</gadget>
<output>2</output>

<gadget id="calculator">3 - 2</gadget>
<output>1</output>

<gadget id="calculator">2 / 1</gadget>
<output>2</output>

<result>2</result>