Not counting numbers with leading 0s, there are 48 = 44 - 43
There are 12 such numbers.
9,000
There are 7200 such numbers.
500 or so.
625 if numbers can have leading 0s, 500 otherwise.
In base ten, there are 9000 four digit number, the numbers are from 1000 to 9999. If you allow leading zeros, then there are 10000 numbers. [0000 - 9999]
7000 - 999 ie 6001 four digit numbers
900 numbers
There are 12 such numbers.
9,000
90
2240
There are 7200 such numbers.
500 or so.
67 of them.
625 if numbers can have leading 0s, 500 otherwise.
81