Wanjiafu Supermarket held promotional activities during the Spring Festival, and my mother wanted to buy 12 pairs of slippers and 9 bags of washing powder. Slippers are 4 yuan a pair, buy three get one free, washing powder is 8 yuan and 3 bags. How much does the mother have to pay in total?
万家福超市春节时搞促销活动，妈妈想买12双拖鞋和9袋洗衣粉．拖鞋4元一双，买三送一，洗衣粉8元3袋．妈妈一共需付多少元？
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<gadget id="calculator">3 * 4 * 3</gadget>
<output>36</output>

<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">3 * 8</gadget>
<output>24</output>

<gadget id="calculator">36 + 24</gadget>
<output>60</output>

<result>60</result>