There are 1, 2, 3, 5, 7, 11 number cards, choose two of them each time to form a true score, put the number cards back, and then choose two of them to form a true score, like Repeatedly, how many different true scores can be obtained in total?
有1、2、3、5、7、11这张数卡，每次选用其中的两张，组成一个真分数后，将数卡放回，再选用其中的两张，组成一个真分数，像这样反复进行，一共可以得以多少个不同的真分数？
<gadget id="calculator">5 / 1</gadget>
<output>5</output>

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

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

<gadget id="calculator">5 + 4 + 3 + 2 + 1</gadget>
<output>15</output>

<result>15</result>