The students collected waste batteries. The fifth grade collected 280, which was 1/4 more than the fourth grade. How many did the fourth grade collect?
同学们收集废电池，五年级收集了280个，比四年级多(1/4)，四年级收集了多少个？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + (1/4)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">280 / (5/4)</gadget>
<output>224</output>

<result>224</result>