1. **State the problem:** Calculate the combination $nCr$ for $n=5$ and $r=3$ using the formula for combinations.
2. **Formula:** The number of combinations of $n$ items taken $r$ at a time is given by:
$$nCr = \frac{n!}{(n-r)!r!}$$
3. **Apply the values:** Substitute $n=5$ and $r=3$:
$$5C3 = \frac{5!}{(5-3)!3!} = \frac{5!}{2!3!}$$
4. **Calculate factorials:**
$$5! = 5 \times 4 \times 3 \times 2 \times 1$$
$$3! = 3 \times 2 \times 1$$
$$2! = 2 \times 1$$
5. **Simplify numerator and denominator:**
$$5C3 = \frac{5 \times 4 \times 3 \times 2 \times 1}{(2 \times 1)(3 \times 2 \times 1)}$$
6. **Cancel common factors:**
$$= \frac{5 \times 4 \times \cancel{3 \times 2 \times 1}}{(2 \times 1) \times \cancel{3 \times 2 \times 1}}$$
7. **Simplify remaining terms:**
$$= \frac{5 \times 4}{2 \times 1} = \frac{20}{2}$$
8. **Final answer:**
$$nCr = 10$$
This means there are 10 ways to choose 3 items from 5 without regard to order.
Combination Calculation 3D8190
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