how many 7 digit numbers can less than 1,048,000 can be made using digits 0,1,4,6,7,8 and 9?
Start from left to right:
We have no choice with the first three digits, they must be 104 or else the final number will be greater than 1048000.
The fourth digit can only be a number less than 8, namely 6 and 7 from what's left.
The remaining three digits can form 6 numbers each, namely
abc
acb
bac
bca
cab
cba
So if you had kept count until now, you would have the answer.