I'm having a bit of trouble understanding what it means for one number to be congruent to another. I have this more technical definition but I was wondering if anyone could put it into more simple terms. What I really want to know is that if say 333 is congruent to 3 mod 10, does that mean that 333 is equivalent to 3 mod 10? Can I replace 333 by just 3? I am looking a lot of examples in my notes and I see numbers being replaced by their congruencies, is that allowed?