Four consecutive odd numbers, the first number is the fourth number (19/21), then what is the sum of the four numbers.
四个连续奇数，第一个数是第四个数的(19/21)，那么四个数的和是多少．
<gadget id="calculator">19 / 21</gadget>
<output>19/21 = around 0.904762</output>

<gadget id="calculator">1 - (19/21)</gadget>
<output>2/21 = around 0.095238</output>

<gadget id="calculator">6 / (2/21)</gadget>
<output>63</output>

<gadget id="calculator">63 + 61 + 59 + 57</gadget>
<output>240</output>

<result>240</result>