A pile of sand has used (5/8) tons, and the remaining (1/4) tons is less than the used one. How many tons is this pile of sand originally?
一堆沙子，用去了(5/8)吨，剩下的比用去的少(1/4)吨，这堆沙子原有多少吨？
<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(5/8) - (1/4)</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(5/8) + (3/8)</gadget>
<output>1</output>

<result>1</result>