A bag contains 5 red and yellow glass balls of the same shape and size. If you don't use your eyes to see, to ensure that you can take out two glass balls with different colors at a time, at least how many must be touched.
在一个袋子里装有形状大小一样的红、黄两种玻璃球各5粒．如果不用眼睛看，要保证一次拿出两粒颜色不相同的玻璃球，至少必须摸出多少来．
<gadget id="calculator">5 + 1</gadget>
<output>6</output>

<result>6</result>