The diameter of the earth is about 12,700 kilometers. The diameter of Saturn is 7,000 kilometers less than 10 times the diameter of the earth. The diameter of Saturn is 25 times the diameter of Mercury. How many kilometers is the diameter of Mercury?
地球的直径约12700千米，土星直径比地球直径的10倍少7000千米，土星直径是水星直径的25倍，水星直径约是多少千米？
<gadget id="calculator">12_700 * 10</gadget>
<output>127_000</output>

<gadget id="calculator">127_000 - 7_000</gadget>
<output>120_000</output>

<gadget id="calculator">120_000 / 25</gadget>
<output>4_800</output>

<result>4_800</result>