There are four numbers A, B, C, and D. The average of the three numbers A, B, and C is 20. The number of D is 12 more than the average of the four numbers. Find the number of D.
有甲、乙、丙、丁四个数，甲、乙、丙三个数的平均数是20，丁数比四个数的平均数多12，求丁数．
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">20 * (3/4)</gadget>
<output>15</output>

<gadget id="calculator">15 + 12</gadget>
<output>27</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">27 / (3/4)</gadget>
<output>36</output>

<result>36</result>