The sum of the four numbers A, B, C, and D is 135. Add 2 to A, subtract 2 from B, multiply C by 2, and divide D by 2. The results are all equal. So what is the number of Ding?
甲、乙、丙、丁四个数的和为135，甲数加上2，乙数减去2，丙数乘以2，丁数除以2，结果都相等．那么丁数为多少．
<gadget id="calculator">2 - 2</gadget>
<output>0</output>

<gadget id="calculator">135 + 0</gadget>
<output>135</output>

<gadget id="calculator">1 + 1 + 0.5 + 2</gadget>
<output>4.5</output>

<gadget id="calculator">135 / 4.5</gadget>
<output>30</output>

<gadget id="calculator">30 * 2</gadget>
<output>60</output>

<result>60</result>