For a project, if Team A is allowed to do it alone, it will be completed 1 day earlier than the prescribed time; if Team B is asked to do it alone, it will take 3 days to complete beyond the prescribed time. If Team A and Team B cooperate for 1 day, the remaining team B will Continue to do it, and it happens to be completed within the specified time. How many days will it take for teams A and B to cooperate?
一项工程，如让甲队单独做，比规定时间提前1天完成；让乙队单独做，则要超过规定时间3天才能完成，如果甲、乙两队合作1天后，剩下的乙队继续做，刚好在规定时间内完成，甲、乙两队合作要多少天完成？
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 + 4</gadget>
<output>6</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/2) + (1/6)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 / (2/3)</gadget>
<output>3/2 = around 1.5</output>

<result>3/2 = around 1.5</result>