Arbor Day, the school bought 100 saplings, the 6th grade planted these saplings (3/5), the 5th grade planted these saplings (1/4), the remaining 4th grade planted these saplings, and the 4th grade planted these saplings What percentage?
植树节，学校买来100棵树苗，六年级种了这些树苗的(3/5)，五年级种了这些树苗的(1/4)，剩下的四年级种，四年级种了这些树苗的几分之几？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (3/5) - (1/4)</gadget>
<output>3/20 = around 0.15</output>

<result>3/20 = around 0.15</result>