Question 97762
How many different telephone numbers are possible within the 537 exchange.  

537 _ _ _ _

The blanks can be the numbers: 0 1 2 3 4 5 6 7 8 OR 9.

There are 10 choices in total; Multiply the numbers to get your answer: 
10*9*8*7*6*5*4*3*2*1 
10*9=90
90*8=720
720*7=5040
5040*6=30240
30240*5=151200
151200*4=604800
604800*3=1814400
1814400*2=3628800
3628800*1=3628800

The final answer is: 3,628,800