Question 982819
{{{P(n,r) = (n!)/((n-r)!)}}}


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{{{C(n,r) = (n!)/(r!(n-r)!)}}}


{{{C(4,4) = (4!)/(4!(4-4)!)}}}


{{{C(4,4) = (4!)/(4!0!)}}}


{{{C(4,4) = (4*3*2*1)/(4*3*2*1*1)}}}


{{{C(4,4) = (24)/(24)}}}


{{{C(4,4) = 1}}}


I'll let you do the last part.