The supply and marketing cooperative has a batch of chemical fertilizers, sell them on the first day (2/9), sell the rest of the first day (1/7) on the second day, and make up for the rest of the second day (1/2) on the third day , At this time, there are still 698 kilograms, how many kilograms of chemical fertilizers were originally there.
供销社有一批化肥，第一天卖出(2/9)，第二天卖出第一天剩下的(1/7)，第三天补进第二天剩下的(1/2)，这时还存有698千克，原来有化肥多少千克．
<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">1 - (2/9)</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(7/9) * (1/7)</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">1 - (2/9) - (1/9)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 + (1/2)</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(2/3) * (3/2)</gadget>
<output>1</output>

<gadget id="calculator">698 / 1</gadget>
<output>698</output>

<result>698</result>