Cut a 2-meter-long rope 3 times, how many decimeters is each length after cutting.
把一根长2米的绳子截3次，截完后每根长多少分米．
<gadget id="calculator">2 * 10</gadget>
<output>20</output>

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

<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<result>5</result>