There are 4 security guards in Dongjie Primary School, they are Uncle Li, Uncle Zhang, Xiao Zhao and Xiao Qian. How many different ways are there to choose 2 of the 4 each time they are on duty? (Write down the possible options in turn below)
东街小学一共有4名保安，分别是李大叔、张大叔、小赵和小钱．如果每次值勤时要从他们4人中选出2人，一共有多少种不同的选法？(把可能的选法依次写在下面)
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

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

<result>6</result>