Xiaofang is 13 years old this year, and Xiaofan is 17 years old this year. How many years later will the sum of their ages be 50 years old? How many
小芳今年13岁，小凡今年17岁，再过多少年，她俩的年龄和是50岁？多少
<gadget id="calculator">50 - 13 - 17</gadget>
<output>20</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<result>10</result>