Author's Notes:

Letter 34: Here.

To my faithful student, Twilight Sparkle,

While I certainly don't begrudge you your hobbies, Twilight, I do feel that perhaps ones a bit more socially involved or immediately useful than increasingly minute digits of Pi may be wise. Sweetie Belle had the right of it, in that it is alright to round Pi, and even in a greater scope, that it is alright to neglect to account for every detail when only the general shape is needed for the end result.

Another example might be temperature. For instance, in chemistry variance of a single tenth of a degree can be explosive, or ruin work if not accounted for, whereas when making coffee - technically a chemical process, though a trivial one - is perfectly happy at a range of temperatures. The context is different and so to is the difference in what you must worry over, and how much.

Your loving mentor,
Princess Celestia

PS. Twilight, did you not already learn the dangers of trying too hard to figure out Pie?