The time for the end-of-semester exam is 90 minutes. Xiao Ming finished the first question in (5/6) hours, and then finished the other questions in (1/3) hour. The rest of the time was used to carefully check the questions he had done, and the exam just ended. How many hours did it take him to check it?
本次数学期末考试时间是90分钟，小明用(5/6)小时做完了第一题，再用(1/3)小时做完了其它的题目．余下的时间用来把所做的题目再仔细检查一遍，就刚好考试结束了，他检查一遍用了多少小时？
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(3/2) - (5/6) - (1/3)</gadget>
<output>1/3 = around 0.333333</output>

<result>1/3 = around 0.333333</result>