There are 600 poplar seedlings in Uncle Wu's nursery. The ratio of poplar seedlings to pine seedlings is 10:7. How many pine seedlings are there?
吴大叔的苗圃里有杨树苗600棵，杨树苗与松树苗棵数的比是10：7，松树苗有多少棵？
<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">600 * (7/10)</gadget>
<output>420</output>

<result>420</result>