A, B, C, and D spent the same amount of money to buy a kind of table tennis balls, and they each took several boxes. It is known that A takes 4 boxes less than B, and C takes 8 boxes less than D. In the end, according to the proportion, A pays C112 yuan, and B pays D72 yuan, so how many boxes does B take more than D?
A、B、C、D四人拿出同样多的钱买一种乒乓球，他们各拿了若干盒．已知A比B少拿4盒，C比D少拿8盒，最后按比例，A还付给C112元，B还应付给D72元，那么B比D多拿多少盒？
<gadget id="calculator">2 * 11</gadget>
<output>22</output>

<gadget id="calculator">22 - 4</gadget>
<output>18</output>

<result>18</result>