Final answer:
To calculate 21P8 on a calculator, perform the permutation formula 21!/(21-8)!, then express the result in scientific notation by adjusting the coefficient and exponent.
Step-by-step explanation:
To evaluate the expression 21P8 using a calculator and express it in scientific notation, first understand what 21P8 means. In permutation notation, 21P8 represents the number of ways to arrange 8 items out of 21 distinct items and is calculated using the formula for permutations, P(n, r) = n! / (n-r)! Here, n is 21 and r is 8. On a calculator, first calculate 21 factorial (21!), then calculate 13 factorial (13!), and divide the former by the latter. After obtaining the result, express it in scientific notation by finding the coefficient that is >=1 and <10 and multiplying it by 10 raised to the appropriate exponent.