/// <summary>
/// Decrements or increments depending on factor
/// </summary>
/// <param name="factor">Multiplication factor (1 or -1) will be applied to the step</param>
private Task Change(double factor = 1)
{
var value = Num.To <T>(Num.From(Value) + Num.From(Step) * factor);
return(SetValueAsync(ConstrainBoundaries(value).value));
}