What is the least positive $x$ with $x + 7 \equiv 3 \pmod{10}$?

Explanation

1. 01

   Subtract 7 from both sides: $x \equiv 3 - 7 = -4 \pmod{10}$.

2. 02

   $-4 + 10 = 6$. Check: $6 + 7 = 13 \equiv 3$.