A and B buy a dictionary together, and the combined money brought by the two of them is 12.6 yuan. If they buy the dictionary separately, the difference between A and B is 4.7 yuan, and the difference between B and B is 3.7 yuan. How much is the dictionary?
甲乙合买一本辞典，他们俩带的钱合起来买还余下12.6元，如果单独买，这本辞典，甲差4.7元，乙差3.7元，这本辞典多少元？
<gadget id="calculator">4.7 + 3.7 + 12.6</gadget>
<output>21</output>

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

<gadget id="calculator">21 / 1</gadget>
<output>21</output>

<result>21</result>