private string CalculateRange(double magnitude, string nextWord, int size)
{
string remainder;
_fromQuantity = new Quantity(nextWord.Substring(size), out remainder);
_toQuantity = _fromQuantity.Clone() as Quantity;
_fromQuantity.Value = magnitude - _fromQuantity.Value;
if (_toQuantity != null) _toQuantity.Value = magnitude + _toQuantity.Value;
return remainder;
}