Mingming and Lele go to the stationery store to buy pen refills. Mingming buys 4 black and 5 blue ones and pays 5 yuan in total, Lele buys 4 black and 6 blue ones and pays 5.6 yuan in total. How much is each black refill?
明明和乐乐去文具店买笔芯．明明买4支黑色的和5支蓝色的共付5元，乐乐买4支黑色的和6支蓝色的共付5.6元．每支黑色笔芯多少钱？
<gadget id="calculator">5.6 - 5</gadget>
<output>0.6</output>

<gadget id="calculator">6 - 5</gadget>
<output>1</output>

<gadget id="calculator">0.6 / 1</gadget>
<output>0.6</output>

<gadget id="calculator">5 * 0.6</gadget>
<output>3</output>

<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>