A football is 35.4 yuan, a basketball is 39.8 yuan, Wang Xiaoming buys a basketball and a football for 100 yuan, how much will the salesperson aunt give Wang Xiaoming back?
一个足球35.4元，一个篮球39.8元，王小明用100元买一个篮球一和一个足球，售货员阿姨给王小明补回多少钱？
<gadget id="calculator">35.4 + 39.8</gadget>
<output>75.2</output>

<gadget id="calculator">100 - 75.2</gadget>
<output>24.8</output>

<result>24.8</result>