How to do permutations on a calculator
Permutations are an important concept in mathematics and have several practical applications in daily life. Whether you’re studying probability or solving a real-life problem, understanding how to perform permutations on a calculator can save time and effort. In this article, we will explore the steps to calculate permutations using a scientific calculator and discuss built-in functions in some popular calculators.
What is a Permutation?
In combinatorics, permutations refer to the arrangement of objects in a specific order. For example, if we have three elements A, B, and C, there are six possible ways to arrange them: ABC, ACB, BAC, BCA, CAB, and CBA. The number of permutations can be determined using the formula:
nPr = n!/(n-r)!
where ‘n’ is the total number of items and ‘r’ is the number of items you want to arrange.
Steps to Perform Permutations on a Scientific Calculator:
1. Determine ‘n’ and ‘r’: Identify the total number of items and the number of items you want to arrange.
2. Calculate Factorial: To perform the factorial function on a calculator, enter the number followed by the factorial key (usually marked with an exclamation point).
3. Divide factorials: Divide n! by (n-r)! using your calculator.
4. Evaluate the Expression: After entering both factorials into your calculator as explained above, press the “=” or “Enter” key to compute the value.
Built-In Permutation Functions:
Some scientific calculators, such as TI-84 Plus or Casio fx-991ES PLUS 2nd edition, come with built-in permutation functions that simplify calculations. You can usually access this function using one of the following methods:
1. Press ‘Shift’, followed by ‘nPr’ or ‘P’: Directly compute nPr values by entering ‘n’, pressing ‘Shift’ or ‘2nd function’, and then pressing the ‘nPr’ or ‘P’ key.
2. Use the Probability Menu: Access your calculator’s probability menu and locate the permutation function.
3. Press ‘Mode’ and Switch to STAT mode: Some calculators require switching modes to access statistics or probability functions, including permutations.
Permutations have practical applications in various domains, and knowing how to perform them on a calculator comes in handy. Focus on understanding the factorial formula for permutation and identify your calculator’s built-in permutation function to simplify the process. Mastering these techniques will make calculating permutations a breeze!