Xiaoxiao has four small balls numbered 1, 2, 3, and 4, and two of them are randomly selected. How many different situations are there to obtain the sum of the numbers of these two small balls?
笑笑有四个编号分别为1，2，3，4的小球，从中随机取出两个，这两个小球求得编号之和有多少种不同的情况．
<gadget id="calculator">2 + 1 + 2</gadget>
<output>5</output>

<result>5</result>