It depends on the mathematics topic being considered. Some mathematics is heavy with algorithms. Memorising these algorithms can be easier if the student teaches a computer by implementing these algorithms.

An example is matrices. Matrix manipulation is mostly algorithms and these can be complex. Finding the determinant of a large matrix is a much simpler problem if implemented in code. It's not hard, just tedious. And tedious tasks are something computers can do well.

Using such a padding scheme makes the message vulnerable to cryptanalysis because the zeroes form a predictable crib in a predictable location.

Wait, what? What's wrong with "top-posting?" (By which I assume you mean writing one's reply to an email at the top, and including the quote of the email being replied to below it.) What kind of nutcase wants to scroll past the old email (that they likely wrote themselves) to read a reply? The quoted email is there for reference in case it is needed. It's not the most important thing, which is what should be at the top.

In the time it takes to find one single top-posted response in context, one can just press the "end" key once, or the "page down" key a few times, and there's the reply at the bottom.
And if you have trouble with bottom posting, the "end" or "page down" keys on your keyboard (depending on your email client) can reach the reply quickly.
If you don't believe me, try reading this message as if it was top posted - from the bottom - and you tell me if this top-posted response is easier to read than it would be if it was written in the usual order.
This waste of time is why many people, including me, loathe top-posting.
It takes a lot longer to read a message full of top-posting in proper sequence than it does to read a message where the sequence of reading is the same as the sequence of posting.
Instead of reading from top to bottom in one smooth sequential flow, one must constantly search the text for the beginning of the next response.
Top-posting is a gross violation of that convention.
Almost all written text in English is read in sequential order from top to bottom.
The trouble with top-posting is that the email that is referenced becomes difficult to read because it flouts an established convention that is seen in most other written English prose.