a dirty atm cash dispenser solution

atmLinqPad.cs

void Main()
{
  var atm = new AtmDispenser();
  var value = 250;
  var notes = atm.GetTheCash (value).Dump($" value: {value}");
  value = 230;
 notes = atm.GetTheCash (value).Dump($" value: {value}");
  value = 370;
  notes = atm.GetTheCash (value).Dump ($" value: {value}");
  value = 260;
  notes = atm.GetTheCash (value).Dump ($" value: {value}");
  value = 40;
  notes = atm.GetTheCash (value).Dump ($" value: {value}");
  value = 50;
  notes = atm.GetTheCash (value).Dump ($" value: {value}");
  value = 60;
  notes = atm.GetTheCash (value).Dump ($" value: {value}");


}

// Define other methods and classes here
public class AtmDispenser {

  public List<int> GetTheCash (int amout) {

    

    // we can have a 210, whic in easy way 

    if (amout < 40 | amout > 1000) {
     throw new IndexOutOfRangeException("Value is not in range");
    }
    
    int numberOf100 = amout  / 100;
    var restAfter100 = amout % 100;
    
    var restAfter100Flag = (restAfter100 / 10);
    // if we will have 10 and 30 we need to decrease amout of 100
    if (restAfter100Flag==1 || restAfter100Flag==3)
    {
      numberOf100--;
    }
  
    
    var remainig50=amout - numberOf100*100;
    int numberOf50 = (remainig50/50);
    var restAfter50 = remainig50 % 50;
    if ((restAfter50  % 20) != 0) {
     numberOf50--; 
    }
    
    var remainig20 = remainig50-numberOf50*50;
    int numberOf20 = remainig20/20;
    return new List<int> {numberOf100, numberOf50, numberOf20};
  }
}