1-(4/7)-(1/7) can be calculated according to how much.
1-(4/7)-(1/7)可以按照多少计算．
<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 - (4/7) - (1/7)</gadget>
<output>2/7 = around 0.285714</output>

<result>2/7 = around 0.285714</result>