Mathematics
Permutations
A permutation is an arrangement of items where order matters, defined by nPr = n! / (n-r)!. Used extensively in probability, statistics, and combinatorial problems. ScanSolve calculates permutations instantly and walks you through each calculation step.
How to Approach Permutations
Input your set size and selection
Enter values for the total number of items (n) and the number of selections (r) for the permutation.
Use the permutation formula
Apply nPr = n! / (n-r)! to find the number of possible arrangements where order is important.
Review the calculated steps
Examine the factorial calculations and understand each step and how the formula arrives at the final permutation count.
Frequently Asked Questions
What's the difference between permutations and combinations?+
Permutations consider order, using nPr = n! / (n-r)!. Combinations disregard order, calculated by nCr = n! / [r!(n-r)!].
How does factorial work in permutations?+
Factorial, denoted n!, is the product of all positive integers ≤ n. It's crucial in calculating arrangements and orders in permutations.
What if r equals n in permutation?+
When r equals n, nPr simplifies to n!, as every item is arranged completely, making λ the only permutation.
Stuck on a Permutations problem?
Snap a photo or type the question. ScanSolve walks you through every step — same as the worked examples above. 5 free solves per day, no card required.