From the 25 natural numbers 1 to 25, two different numbers are taken each time so that their sum is a multiple of 4. How many different ways are there?
从1～25这25个自然数中，每次取出两个不同的数，使它们的和是4的倍数，共有多少种不同的取法．
<gadget id="calculator">3 / 3</gadget>
<output>1</output>

<gadget id="calculator">7 * 6</gadget>
<output>42</output>

<gadget id="calculator">5 + 4 + 3 + 2 + 1 + 42 + 5 + 4 + 3 + 2 + 1</gadget>
<output>72</output>

<result>72</result>