Question

find the difference between the greatest and the smallest number formed by using 3,5,7,9 and 4, one digit can be used once only

Answer 1

Let the smallest number=34579
Let the greatest number=97543
$difference = 97543 - 34579 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 62964$