Question

P(12,3)=12!/(12-3)!
=12!/9!
=12*11*10
=1320
the number of permutations is 1320

can someone check over this please?

Answer 1

You have the correct steps and final answer. Nice job.

Answer 2

Looks good!
Also you can avoid that formula when r is small :

P(12,3) = 12*11*10

Answer 3

just keep multiplying backwards "r" times

Answer 4

for example :

P(12, 4) = 12*11*10*9

Answer 5

thank you!!