The pony walks 450 meters uphill, 6 minutes downhill, 90 meters per minute, how many meters in total?
小马上山走450米，下山走6分钟，每分钟走90米，一共走多少米？
<gadget id="calculator">6 * 90</gadget>
<output>540</output>

<gadget id="calculator">450 + 540</gadget>
<output>990</output>

<result>990</result>