What Is This Tool?
This calculator computes combinations, which represent the total ways to select a subset of items from a larger set without regard to order. It uses the formula C(n, r) = n! / (r!(n − r)! ) to provide precise integer results based on factorial calculations.
How to Use This Tool?
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Enter the total number of items (n) in the set.
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Input the number of items to select (r) from the set.
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Click the calculate button to compute the combination value.
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Review the result showing the number of unique groups possible.
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Adjust input values as needed to explore different scenarios.
Key Features
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Calculates combinations using exact factorial formulas with high accuracy
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Supports input for total items (n) and number chosen (r)
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Delivers integer results representing unique group counts
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Browser-based and easy to use without needing software installation
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Suitable for probability, statistical analysis, and combinatorial applications
Examples
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To find how many ways to choose 3 items from 5, set n = 5 and r = 3.
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The calculator uses the formula: C(5, 3) = 5! / (3! × 2!).
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Since 5! = 120, 3! = 6, and 2! = 2, the calculation is 120 / (6 × 2) = 10.
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This means there are 10 unique groups of 3 items possible from 5.
Common Use Cases
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Calculating probabilities in statistics and probability theory.
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Analyzing possible card combinations in card games.
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Determining lottery odds based on chosen numbers.
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Solving combinatorial mathematics problems requiring group counts.
Tips & Best Practices
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Ensure the values for n and r are within reasonable sizes to avoid performance issues.
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Double-check inputs to guarantee accurate calculation results.
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Use the calculator for educational, analytical, or recreational combinatorial tasks.
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Remember the order does not matter in combinations; for order-sensitive cases, use permutations.
Limitations
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Very large values of n can cause factorial overflow, affecting reliability.
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Performance may degrade with extremely high inputs depending on your device or browser.
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The tool does not handle permutations or ordered selections.
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Accuracy depends on the computational capability of the environment running the calculator.
Frequently Asked Questions
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What does the combination formula C(n, r) represent?
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It calculates the number of ways to select r items from a total of n items where the order of selection does not matter.
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Can this calculator handle very large numbers?
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While it calculates exact values, extremely large inputs for n may lead to factorial overflow or slower performance depending on the device or browser.
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How is combination different from permutation?
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Combinations do not consider order, whereas permutations count different orders as different outcomes; this calculator only computes combinations.
Key Terminology
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Combination
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A selection of items from a larger set where the order does not matter.
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Factorial (n!)
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The product of all positive integers from 1 up to n.
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n
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The total number of items in the set.
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r
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The number of items to choose from the total set.