# Combination with Replacement Calculator

Instructions:
• Enter 'n' (total items) and 'r' (selection count).
• Check "Allow Zero Selection" if needed.
• Click "Calculate" to compute the result.
• View the result and calculation details below.
• Use "Calculation History" to track previous calculations.
• Click "Clear" to reset the inputs and results.
• Click "Copy Result" to copy the result to the clipboard.
Result:

Calculation Details

Calculation History
CalculationResult

A combination with replacement calculator is a tool that allows users to calculate the number of combinations of a given set of items with replacement. This means that each item can be chosen more than once.

## Concepts

The following are some of the key concepts that underlie combination with replacement calculators:

• Set: A set is a collection of distinct objects.
• Combination: A combination is a subset of a set in which the order of the items does not matter.
• Replacement: Replacement means that each item can be chosen more than once.

## Formulae

The following formula is used to calculate the number of combinations of a given set of items with replacement:

``````nCr = n^r
``````

where:

• n is the number of items in the set
• r is the number of items in the combination

For example, if you have a set of 3 items and you want to calculate the number of combinations of 2 items with replacement, you would use the following formula:

``````3C2 = 3^2 = 9
``````

Therefore, there are 9 combinations of 2 items from a set of 3 items with replacement.

## Benefits of using a combination with replacement calculator

There are several benefits to using a combination with replacement calculator, including:

• Accuracy: Combination with replacement calculators are very accurate, as they use sophisticated mathematical algorithms to perform their calculations.
• Convenience: Combination with replacement calculators can save users a lot of time and effort, as they can perform complex calculations quickly and easily.
• Flexibility: Combination with replacement calculators can be used to calculate the number of combinations of any set of items with replacement, regardless of the size of the set.
• Versatility: Combination with replacement calculators can be used in a variety of fields, including mathematics, probability, and statistics.

## Interesting facts about combinations with replacement

• The number of combinations of a set of items with replacement is always greater than or equal to the number of combinations of the same set of items without replacement.
• The number of combinations of a set of items with replacement is equal to the number of ways to choose the order of the items in the set and then multiply by the number of times that each order is counted.
• The number of combinations of a set of items with replacement can be used to calculate the probability of certain events, such as the probability of getting a certain number of heads on a coin toss.

## Scholarly references

• Kenneth H. Rosen: Discrete Mathematics and Its Applications, 8th Edition, McGraw-Hill Education, 2019
• Susan S. Epp: Discrete Mathematics with Applications, 5th Edition, Cengage Learning, 2018
• Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, and Clifford Stein: Introduction to Algorithms, 3rd Edition, MIT Press, 2009

## Conclusion

Combination with replacement calculators are a valuable tool for anyone who needs to calculate the number of combinations of a given set of items with replacement. They are accurate, convenient, flexible, and versatile. Combination with replacement calculators can be used in a variety of fields, including mathematics, probability, and statistics.

## Example of using a combination with replacement calculator

Let’s say you are a gardener and you want to know how many different combinations of plants you can plant in a garden with 5 different types of plants. You could use a combination with replacement calculator to do this.

To do this, you would enter the following information into the calculator:

• Number of items in the set: 5
• Number of items in the combination: 3

The calculator would then display the following result:

``````Number of combinations: 125
``````

Therefore, there are 125 different combinations of 3 plants that you can plant in a garden with 5 different types of plants, even if you plant the same type of plant multiple times.

Combination with replacement calculators can be used to calculate the number of combinations of any set of items with replacement, regardless of the size of the set. This makes them a valuable tool for a variety of applications.

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