The 250mL pure milk of a certain brand is priced at 2.1 yuan per box. On the Children's Day, the shopping mall is holding a promotion. It only costs 45.6 yuan to buy a box. My mother bought a box of this kind of milk, which is much less than usual. Yuan? (24 boxes per carton)
某品牌的250mL装的纯牛奶每盒售价为2.1元，六•一儿童节这天商场搞促销活动，买一箱只需要45.6元，妈妈买了一箱这样的牛奶，比平时节约了多少元？(每箱24盒)
<gadget id="calculator">2.1 * 24</gadget>
<output>50.4</output>

<gadget id="calculator">50.4 - 45.6</gadget>
<output>4.8</output>

<result>4.8</result>