That's fine, but are you looking for the answer, or the formal mathematical proof that 2 + 2 = 4? How would a mathematician feel if you asked them to write the

That's fine, but are you looking for the answer, or the formal mathematical proof that 2 + 2 = 4? How would a mathematician feel if you asked them to write the proof for it? They would probably feel insulted too. In this day and age there is no need to prove that 2 + 2 = 4 (because it has already been proven), just like there is no need to implement a binary search tree (because the vast majority of tools already have). If your job will involve developing such tools, fine, but that's not the vast majority of dev jobs.