Question

Permutation of $n$ different things taken ____ at a time is denoted by ${{}^{n}P}_3$.

Answer 1

Permutation is denoted by $P$

Total number of things $A$

Number of different things $n$

$\Rightarrow$ Permutation of $n$ different things

Taken $r$ at a time = ${{}^{n}P}_r$

Here $r$ is $3$

Hence, the answer is $3$.