Mom wholesales a dozen (12 pairs) of socks with a retail price of 3.5 yuan per pair in the wholesale market, and spends 35.4 yuan. How much is each pair of socks cheaper?
妈妈在批发市场批发了一打(12双)零售价为每双3.5元的袜子，花了35.4元，每双袜子便宜多少钱？
<gadget id="calculator">3.5 * 12</gadget>
<output>42</output>

<gadget id="calculator">42 - 35.4</gadget>
<output>6.6</output>

<gadget id="calculator">6.6 / 12</gadget>
<output>0.55</output>

<result>0.55</result>