A pile of watermelons (5/8) is exactly 400 kg. (7/16) of the total number of watermelons in this pile were sold on the first day, how many kilograms are left unsold?
一堆西瓜的(5/8)正好是400千克．第一天卖出了这堆西瓜总数的(7/16)，还剩多少千克没有卖出？
<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">400 / (5/8)</gadget>
<output>640</output>

<gadget id="calculator">7 / 16</gadget>
<output>7/16 = around 0.4375</output>

<gadget id="calculator">640 * (7/16)</gadget>
<output>280</output>

<gadget id="calculator">640 - 280</gadget>
<output>360</output>

<result>360</result>