420 students from Qing'an Primary School participated in the physical education standard test. As a result, 25% of them were excellent, (3/5) were qualified, and how many were unqualified?
庆安小学420人参加体育达标测试，结果有25%的人达到优秀，(3/5)的人合格，不合格的有多少人？
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

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

<gadget id="calculator">420 * (3/20)</gadget>
<output>63</output>

<result>63</result>