The students participated in the tree planting activity. Boys planted 40 trees and girls planted 50 trees. By what percentage are boys less planted than girls?
同学们参加植树活动．男生植了40棵，女生植了50棵．男生比女生少植百分之几？
<gadget id="calculator">50 - 40</gadget>
<output>10</output>

<gadget id="calculator">10 / 50</gadget>
<output>1/5 = around 0.2</output>

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