Assign the digits from left to right, using the largest possible digit in each case. Don't forget to reserve an even digit for the last position.
You get the largest number if you sort the digits, from largest to smallest.
Using the digits 12279, the largest number that can be represented is 97,221.
If the digits are only used once, each, the largest possible number would be 97,531
The largest odd number that can be made with those digits is 9407 .
The largest even number that can be made with those digits is 9740 .
the largest five digit number that can be formed using the digits 7 and 9 is 97,000
9650 is the largest formed by re-ordering the digits.