title: Have the function MathChallenge(num) take the num parameter being passed and determine the largest double digit number within the whole number
body: <p>Have the function MathChallenge(num) take the num parameter being passed and determine the largest double digit number within the whole number. For example: if num is 4759472 then your program should return 94 because that is the largest double digit number. The input will always contain at least two positive digits.</p>
  <p>I am looking for a solution to this problem in dart programming language.</p>