Question

the tip of the iceberg - Yes, I know he has spelling difficulties, but that's just the tip of the iceberg as far as his problems in English are concerned.  - You think everything's now going to be ok, but that was just the tip of the iceberg.  - But each of these is just the tip of the iceberg. Underlying each is a much larger, deeper, and more important mathematical idea.  - The media would have been filled with speculation that the arrested man was only the tip of the iceberg of a much larger and more dangerous conspiracy.

Accepted Answer

the small, visible part of a large problem The Titanic sank when it hit an iceberg.

Idiom	the tip of the iceberg
Definition	the small, visible part of a large problem
Examples	- Yes, I know he has spelling difficulties, but that's just the tip of the iceberg as far as his problems in English are concerned. - You think everything's now going to be ok, but that was just the tip of the iceberg. - But each of these is just the tip of the iceberg. Underlying each is a much larger, deeper, and more important mathematical idea. - The media would have been filled with speculation that the arrested man was only the tip of the iceberg of a much larger and more dangerous conspiracy.
Note	The Titanic sank when it hit an iceberg.

Tip Iceberg Small Visible Part Large Problem I