Xiaohua's family planted 16 trees this year, which is 4 less than last year. How much less is planted this year than last year?
小华家今年植树16棵，比去年少植了4棵，今年比去年少植了百分之几？
<gadget id="calculator">16 + 4</gadget>
<output>20</output>

<gadget id="calculator">4 / 20</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>