What is the greatest odd number that uses 3 4 5 once each?

Answer 1

Well, honey, the greatest odd number you can make using 3, 4, and 5 only once each is 543. It's odd because the last digit is 3. So, there you have it, darling, 543 is the winner in this odd number game.

Answer 2

If the answer is limited to using the 3 3 numbers and no others then 543, 453 345, and 435 are the only answers but as the number could have any other numbers interposed between these 3 the answer is pretty much unlimited (e.g 1,267,893,126,784,129,8750)

Answer 3

543