1. The problem is to find the number of combinations of 52 items taken 2 at a time, denoted as $52 \choose 2$. 2. The formula for combinations is: $$ {n \choose r} = \frac{n!}{r!(n-r)!} $$ where $n$ is the total number of items, and $r$ is the number of items chosen. 3. For $52 \choose 2$, substitute $n=52$ and $r=2$: $$ {52 \choose 2} = \frac{52!}{2!(52-2)!} = \frac{52!}{2! \times 50!} $$ 4. Simplify the factorial expression by canceling $50!$: $$ \frac{52 \times 51 \times 50!}{2 \times 1 \times 50!} = \frac{52 \times 51}{2} $$ 5. Calculate the numerator: $$ 52 \times 51 = 2652 $$ 6. Divide by 2: $$ \frac{2652}{2} = 1326 $$ 7. Therefore, the number of combinations is $1326$.