In a reading competition, the prescribed reading time is 5 minutes. Xiaoxiao prepared a 980-word reading material. During the trial reading before the competition, she spent 7 points. If she read at this speed, how many words must Xiaoxiao delete at least to ensure that she does not overtime?
在一次朗读比赛中，规定朗读时间为5分钟．笑笑准备了一份980字的朗读材料，在比赛前试读时，她用了7分，如果按照这样的朗读速度，笑笑至少要删掉多少字才能确保不超时？
<gadget id="calculator">980 / 7</gadget>
<output>140</output>

<gadget id="calculator">140 * 5</gadget>
<output>700</output>

<gadget id="calculator">980 - 700</gadget>
<output>280</output>

<result>280</result>