Xiaoqiang completed 80% of the plan by doing math problems. If he does 20 more questions, it will exceed 20% of the plan. How many questions does Xiaoqiang plan to do?
小强做数学题，完成了计划的80%，如果再做20道题就超过计划的20%，小强计划做多少道题？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) + (1/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">20 / (2/5)</gadget>
<output>50</output>

<result>50</result>