The minuend is (8/15), the ratio of the subtrahend to the difference is 1:3, what is the difference.
被减数是(8/15)，减数与差的比是1：3，差是多少．
<gadget id="calculator">8 / 15</gadget>
<output>8/15 = around 0.533333</output>

<gadget id="calculator">1 + 3</gadget>
<output>4</output>

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

<gadget id="calculator">(8/15) * (3/4)</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>