Xiao Ming calculated 25 competition questions, got 6 points if he got one right, and deducted 4 points if he got one wrong. As a result, Xiao Ming got 110 points. How many questions did Xiao Ming get wrong?
小明计算25道竞赛题，做对一道得6分，做错一道扣4分，结果小明得了110分，小明错了多少道题．
<gadget id="calculator">6 * 25</gadget>
<output>150</output>

<gadget id="calculator">150 - 110</gadget>
<output>40</output>

<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<gadget id="calculator">40 / 10</gadget>
<output>4</output>

<result>4</result>