What is $(15^{2} + 26) \bmod 4$?

Explanation

1. 01

   Reduce before squaring: $15 \equiv 3$, so $15^{2} \equiv 9 \equiv 1 \pmod{4}$; and $26 \equiv 2$.

2. 02

   $1 + 2 = 3$. Check: $225 + 26 = 251 = 4 \times 62 + 3$.