There are 120 sixth graders in a certain school who have reached the physical education standard, accounting for (4/5) of the sixth graders. How many people are not up to the standard?
某校六年级体育达标人数120人，占六年级人数的(4/5)，未达标的有多少人？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">120 / (4/5)</gadget>
<output>150</output>

<gadget id="calculator">150 - 120</gadget>
<output>30</output>

<result>30</result>