There are three colored ribbons, 20 meters long, 24 meters long and 28 meters long respectively. Now cut them into small pieces of the same length, and no surplus is allowed. How long is each paragraph?
有三根彩带，分别长20米，24米和28米，现在把它们剪成同样的长的小段，不许剩余．每段最长是多少？
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<result>4</result>