Mom is on a business trip. She left on June 15th and arrived home on August 4th. How many days in total?
妈妈出差，她于6月15日出发，8月4日到家，一共出差多少天？
<gadget id="calculator">30 - 15</gadget>
<output>15</output>

<gadget id="calculator">15 + 31 + 4</gadget>
<output>50</output>

<result>50</result>