coal mining team completed 45% of the plan in the first half of April, and completed (3/4) of the plan in the second half of April, resulting in an overproduction of 100 tons. How many tons of coal is planned for April?
某采煤队四月份上半月完成计划的45%，下半月又完成计划的(3/4)，结果超产100吨，四月份计划产煤多少吨？
<gadget id="calculator">45 / 100</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(3/4) - 1</gadget>
<output>-1/4 = around -0.25</output>

<gadget id="calculator">(9/20) + (-1/4)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">100 / (1/5)</gadget>
<output>500</output>

<result>500</result>