The three raced in the 60-meter race. It took Li Qiang 9.4 seconds to complete the race, Chen Gang was 0.3 seconds faster than him, and Zhang Hua was 0.1 seconds faster than Chen Gang. How many seconds did Zhang Hua take?
三人进行60米比赛，李强跑完全程用了9.4秒，陈刚比他快0.3秒，张华比陈刚快0.1秒，张华用了多少秒？
<gadget id="calculator">9.4 - 0.3 - 0.1</gadget>
<output>9</output>

<result>9</result>