Among the 20 natural numbers from 1 to 20, what is the sum of all even numbers more than the sum of odd numbers?
在1到20这20个自然数中，所有的偶数的和比奇数的和多多少
<gadget id="calculator">1 * 2</gadget>
<output>2</output>

<gadget id="calculator">1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19</gadget>
<output>100</output>

<gadget id="calculator">20 - 100</gadget>
<output>-80</output>

<gadget id="calculator">2 + 4 + 6 + 8 + 10 + 12 + 14 + 16 + 18 + (-80)</gadget>
<output>10</output>

<result>10</result>