Good analogy! I always use "Skip i rows and j columns", thanks to you I'll add a story behind that from now on.
Elaborating your answer for completeness' sake.
Skip 40 rows and 50 columns
=> Skip 40*(Size of column) elements + 50 elements.
=> Skip 40*100 elements + 50 elements.
=> Skip 4050 elements.
Here, the element is char, and 1 char takes up 1 Byte.
So, 4050 Bytes. => 4050th address.
Also, note that this approach works when the initial element is at A. If somewhere else like A[-5], then skip accordingly.