The school shipped 5 tons of sand. (2/7) is used to build the wall, and (3/8) is used to repair the playground. How much is left?
学校运来5吨沙子．砌墙用去它的(2/7)，修运动场用去它的(3/8)，还剩几分之几？
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

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

<gadget id="calculator">1 - (2/7) - (3/8)</gadget>
<output>19/56 = around 0.339286</output>

<result>19/56 = around 0.339286</result>