Find the law and calculate: 9999+9998+9997+9996+9995+9994+9993.
找规律，计算：9999+9998+9997+9996+9995+9994+9993．
<gadget id="calculator">9_999 + 9_998 + 9_997 + 9_996 + 9_995 + 9_994 + 9_993</gadget>
<output>69_972</output>

<result>69_972</result>