For a pile of sand, (7/8) tons are used for the first time, and (3/4) tons are used less than the second time, how many tons are used for the two times?
一堆沙，第一次用去(7/8)吨，比第二次少用(3/4)吨，两次共用多少吨？
<gadget id="calculator">7 / 8</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(7/8) + (7/8) + (3/4)</gadget>
<output>5/2 = around 2.5</output>

<result>5/2 = around 2.5</result>