After adding the numerator and denominator of (5/19), it can be simplified to (1/3).
(5/19)的分子、分母同时加上多少后，可化简为(1/3)．
<gadget id="calculator">3 / 1</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/3) * 19</gadget>
<output>19/3 = around 6.333333</output>

<gadget id="calculator">(19/3) - 5</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(4/3) / (2/3)</gadget>
<output>2</output>

<result>2</result>