it's not rocket science idiom humorous (also it doesn't take a rocket scientist)
并不太难；并非特别复杂
used to say that you do not think that something is very difficult to do or to understand
Come on, it's only a crossword, it's not rocket science. 来吧，不就是个填字游戏嘛，并不是那么难。
Drugs equals crime. It doesn't take a rocket scientist to figure that one out. 毒品等于犯罪。这个道理十分显浅，不是火箭科学家才懂的。
See also: brain surgery