For a road, the full length (1/4) is repaired on the first day, and the full length (1/2) is repaired on the second day. The second day is 100 meters longer than the first day. How long is this road?
一条路，第一天修全长的(1/4)，第二天修全长的(1/2)，第二天比第一天多修100米，这条路多长？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/2) - (1/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">100 / (1/4)</gadget>
<output>400</output>

<result>400</result>