Xiaoli and her father are 55 years old this year. Five years ago, her father was four times as old as Xiaoli. How old is Xiaoli this year?
今年小丽和爸爸共55岁，5年前爸爸年龄是小丽的4倍，今年小丽多少岁？
<gadget id="calculator">55 - 5 - 5</gadget>
<output>45</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">45 / 3</gadget>
<output>15</output>

<gadget id="calculator">15 + 5</gadget>
<output>20</output>

<result>20</result>