certain project can be completed by A alone in 63 days, and then by B alone in 28 days. If A and B work together, it will take 48 days to complete. Now B will do it alone for 56 days first, and then A will continue to finish it. How many days will A still need to do it?
某工程先由甲独做63天，再由乙独做28天就可以完成，如果甲、乙合做需48天完成．现在乙先独做56天，然后再由甲接着做完，那么甲还需做多少天才能完成？
<gadget id="calculator">1 / 48</gadget>
<output>1/48 = around 0.020833</output>

<gadget id="calculator">28 / 48</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">1 - (7/12)</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">63 - 28</gadget>
<output>35</output>

<gadget id="calculator">(5/12) / 35</gadget>
<output>1/84 = around 0.011905</output>

<gadget id="calculator">(1/48) - (1/84)</gadget>
<output>1/112 = around 0.008929</output>

<gadget id="calculator">(1/112) * 56</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">(1/2) / (1/84)</gadget>
<output>42</output>

<result>42</result>