In a running competition, Li Ming took 8.6 seconds, Xiaohong was 0.05 seconds slower than Li Ming, and Zhang Qiang was 0.25 seconds faster than Xiaohong. How many seconds did Zhang Qiang spend?
一次跑步比赛，李明用了8.6秒，小红比李明慢0.05秒，张强比小红快0.25秒．张强用了多少秒？
<gadget id="calculator">0.05 - 0.25</gadget>
<output>-0.2</output>

<gadget id="calculator">8.6 + (-0.2)</gadget>
<output>8.4</output>

<result>8.4</result>