The formula to calculate the Number of Combinations (Nc) is:
\[ Nc = \frac{C!}{n!(C-n)!} \]
Where:
Let's say the total number of items (C) is 5 and the number of items to choose (n) is 3. Using the formula:
\[ Nc = \frac{5!}{3!(5-3)!} = \frac{120}{6 \cdot 2} = 10 \]
So, the Number of Combinations (Nc) is 10.