There is a pile of walnuts on the beach. The monkey ate 2/5 of the pile of walnuts on the first day and threw 4 into the sea; The number of walnuts left (5/8), if there are 6 walnuts left the next day, how many walnuts are there on the beach?
海滩上有一堆核桃，第一天猴子吃掉了这堆核桃的(2/5)，又将4个扔到大海中；第二天猴子吃掉的核桃数加上3个就是第一天所剩核桃数的(5/8)，若第二天剩下6个核桃，问海滩上原有多少个核桃？
<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">6 - (5/2) - 3</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">4 + (1/2)</gadget>
<output>9/2 = around 4.5</output>

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

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(3/5) - (3/8)</gadget>
<output>9/40 = around 0.225</output>

<gadget id="calculator">(9/2) / (9/40)</gadget>
<output>20</output>

<result>20</result>