Xiaoyou and Xiaodong participate in the sports meeting and participate in one of the four events of long jump, high jump, 100 meters, and 200 meters (the two can apply for the same event at the same time), how many registration methods can they have?
小有和小冬参加运动会，参加在跳远、跳高、100米、200米四个项目中的一项比赛(可以两人同时报同一项目)，两人一共可以有多少种报名方式？
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">4 * (3/2)</gadget>
<output>6</output>

<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<result>10</result>