Any pair of digits (not including 0), can be used to generate 14 four-digit numbers. If one of the digits is 0, only seven will start with a non-zero digit.
There are 12 such numbers.
9,000
There are 7200 such numbers.
625 if numbers can have leading 0s, 500 otherwise.
Any pair of digits (not including 0), can be used to generate 14 four-digit numbers. If one of the digits is 0, only seven will start with a non-zero digit.
7000 - 999 ie 6001 four digit numbers
900 numbers
There are 12 such numbers.
9,000
90
Allowing numbers that start with zero, the answer is 6!/(2!*2!) = 720/(2*2) = 180
2240
There are 7200 such numbers.
625 if numbers can have leading 0s, 500 otherwise.
67 of them.
500 or so.