The four numbers A, B, C, and D are paired in pairs to form six pairs. The average numbers of these six pairs are 12, 13, 15, 17, 19, and 20 respectively. So what is the sum of these four numbers?
A、B、C、D四个数两两配对，可以配成六对，这六对的平均数分别是12、13、15、17、19、20．那么原来这四个数的和是多少．
<gadget id="calculator">12 + 13 + 15 + 17 + 19 + 20</gadget>
<output>96</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">96 * (2/3)</gadget>
<output>64</output>

<result>64</result>