In a subtraction formula, the subtrahend is just the difference (2/5), then the difference is the number of the minuend.
在一道减法算式里，减数正好是差的(2/5)，那么差是被减数的多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">5 * (2/5)</gadget>
<output>2</output>

<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<gadget id="calculator">(2/5) / 7</gadget>
<output>2/35 = around 0.057143</output>

<gadget id="calculator">5 * (2/35)</gadget>
<output>2/7 = around 0.285714</output>

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