1
1
Only four numbers:20233032
Total possible 4-digit numbers= 1000, 1001,...,9999 = 9000 Total with same digit numbers = 1111,2222,...,9999 = 9 9000 - 9 = 8991
There are 3 values (1, 2, 3) for each of the 4 digits. Therefore, there are 3*3*3*3 or 81 four digit numbers that can be formed.
9630
It is 415968.
Four digit numbers span from 1000 to 9999. This totals (9999-1000) +1 = 9000 different four digit numbers
There are 9 x 10 x 10 x 10, or 9000 four-digit number that can be formed if the leading digit cannot be zero.
10,000
pizza
4*3*2*1 = 24
4: 1999,9199,9919,9991