Mom goes to the store to buy things. She buys a pair of trousers and spends half of the money she brings, buys a stationery box and spends 5.1 yuan, and buys a pen and uses half of the remaining money. At this time, there is still 2.1 yuan left. How much money does mother bring in total? shop.
妈妈去商店买东西，她买一条裤子用去所带钱的一半，买文具盒用去5.1元，买钢笔又用去余下钱的一半，这时还剩2.1元，妈妈一共带多少元钱去商店．
<gadget id="calculator">5.1 + 2.1 + 2.1</gadget>
<output>9.3</output>

<gadget id="calculator">9.3 * 2</gadget>
<output>18.6</output>

<result>18.6</result>