It is known that the average of the four numbers A, B, C, and D is 12, and the average of the two numbers A and B is 8. What is the average of the two numbers C and D?
已知甲、乙、丙、丁四个数的平均数是12，甲、乙两数的平均数是8，丙、丁两数的平均数是多少．
<gadget id="calculator">12 * 4</gadget>
<output>48</output>

<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<gadget id="calculator">48 - 16</gadget>
<output>32</output>

<gadget id="calculator">32 / 2</gadget>
<output>16</output>

<result>16</result>