A rope is 10 meters long, and 30 decimeters are used up, how many meters are left?
一根绳子长10米，用去30分米，还剩多少米？
<gadget id="calculator">30 / 10</gadget>
<output>3</output>

<gadget id="calculator">10 - 3</gadget>
<output>7</output>

<result>7</result>