Subtract 8 from the numerator of (10/45), to keep the size of the fraction unchanged, the denominator should be reduced to the original value.
(10/45)的分子减去8，要使分数的大小不变，分母应缩小到原来的多少．
<gadget id="calculator">10 - 8</gadget>
<output>2</output>

<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>