A certain field used 28 tons of water in September, and saved (4/7) in October compared with September. How many tons of water are planned for October?
某场九月份用水28吨，十月份比九月份节约(4/7)，十月份计划用水多少吨？
<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">1 - (4/7)</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">28 * (3/7)</gadget>
<output>12</output>

<result>12</result>