Grandma bought a 5-meter-long red ribbon to weave a Chinese knot. To weave a Chinese knot, it takes 105 centimeters of red ribbon. How many centimeters are left after weaving two Chinese knots?
奶奶买了一根5米长的红丝带编中国结，编制一个中国结要用红丝带105厘米，编了两个中国结后还剩下多少厘米？
<gadget id="calculator">5 * 100</gadget>
<output>500</output>

<gadget id="calculator">105 * 2</gadget>
<output>210</output>

<gadget id="calculator">500 - 210</gadget>
<output>290</output>

<result>290</result>