N and M are each 3-digit integers

N and M are each 3-digit integers. Each of the numbers 1, 2, 3,4,5 and 6 is a digit of either N or M. What is the smallest possible positive difference between N and M?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #39774