The fifth grade of Guangming Primary School held a mathematics competition. There were 10 questions in total. One correct answer was worth 10 points, and 5 points were deducted for wrong answers or non-answers. Xiao Ding Ding got 70 points. How many questions did he answer correctly? (Solution of column equations)
光明小学五年级举行数学竞赛，一共10道题，答对一题得10分，答错或不答倒扣5分，小丁丁得了70分，他答对了几道题？(列方程解题)
<gadget id="calculator">5 * 10</gadget>
<output>50</output>

<gadget id="calculator">50 + 70</gadget>
<output>120</output>

<gadget id="calculator">10 + 5</gadget>
<output>15</output>

<gadget id="calculator">120 / 15</gadget>
<output>8</output>

<result>8</result>