A project requires 10 days and 12 days to be completed by A and B respectively. Now the two teams cooperate and each rest for a few days in the middle, and they share 9 days to complete the project. The ratio of A and B’s workload is 2:3. How many days did A rest?
一项工程，甲、乙各自独做需10天、12天完成，现两队合作，中途各休息了若干天，前后共用9天完成，完工时甲、乙工作量的比是2：3，甲休息了几天？
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(2/5) / (1/10)</gadget>
<output>4</output>

<gadget id="calculator">9 - 4</gadget>
<output>5</output>

<result>5</result>