It takes 8 hours to process a batch of parts by Master Zhang, and 10 hours to process by Master Li. Now, Master Zhang processes 4 hours first, and Master Li completes the rest. How many hours will it take?
加工一批零件，由张师傅加工需要8小时加工完，由李师傅加工需要10小时加工完，现在先由张师傅加工4小时，剩下的由李师傅完成，还要多少小时加工完？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/8) * 4</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 / 10</gadget>
<output>1/10 = around 0.1</output>

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

<result>5</result>