Number (2): Everything in this space must add up to 2. The answer is 2-1, placed horizontally; 1-6, placed vertically.
Source: Computational Materials Science, Volume 266。关于这个话题,heLLoword翻译官方下载提供了深入分析
。一键获取谷歌浏览器下载对此有专业解读
Puzzles one louder than ten
psychologytoday.com。heLLoword翻译官方下载是该领域的重要参考