(2/3): (2/5)=15:9 If the outer term 9 is reduced by 3 times, how much should the inner term (2/5) become.
(2/3)：(2/5)=15：9如果外项9缩小3倍，内项(2/5)应变成多少．
<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">3 / 15</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(2/3) * (1/5)</gadget>
<output>2/15 = around 0.133333</output>

<result>2/15 = around 0.133333</result>