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Data & Financing

Permutation calculator

Count ordered selections with $_{n} P_{r}$ .

Relevant formula

_{n} P_{r} = \frac{n !}{( n - r )!},_{n} C_{r} = \frac{n !}{r ! ( n - r )!}

∴

01Write first

Record the original equation, known values, units, and restrictions before entering numbers.

02Compare steps

Use the displayed sequence to check your own method rather than copying it without explanation.

03Round last

Keep enough precision during the work and apply the course’s required rounding at the final step.

04Verify

Substitute solutions, check units and domain restrictions, and ask whether the result is reasonable.