What is the difference between the sum of all composite numbers within 10 (including 10) and the sum of all prime numbers.
10以内(包含10)所有合数的和与所有质数的和相差多少．
<gadget id="calculator">4 + 6 + 8 + 9 + 10</gadget>
<output>37</output>

<gadget id="calculator">2 + 3 + 5 + 7</gadget>
<output>17</output>

<gadget id="calculator">37 - 17</gadget>
<output>20</output>

<result>20</result>