Social Security Numbers A social security number consists of nine digits. How many different social security numbers are possible if repetition of digits is permitted?

Question

andijo76 · Answer

There is a possibility of 10 numbers in each place. There are 9 places in a social security number (123-456-789)…
10^9=10x10x10x10x10x10x10x10x10=1 billion
=1 billion combinations
is this right?????

akshay_budhkar · Answer

Can u have zero as ur first digit?

farmdawgnation · Answer

I believe 0 is a valid first digit.

anonymous · Answer

You calculate it with the formula 10*10*10*10, since each of the four codes has 10 possible digits. 

Social security numbers are the same. 

You specified that numbers and letters can not be repeated. Therefore the 3 numbers will be 10*9*8. The two letters will be 26*25. Therefore the total possibilities will be 10*9*8*26*25.