public void GivenVariableNumberWhenSubtractVariableNumberFromSourceShouldDoThat()
      {
         var uom = _ftUnitOfMeasure.ToModelUom();
         var firstValue = new NumericValue(uom, 24.68);
         var secondValue = new NumericValue(uom, 10.11);
         var firstNumber = new NumericRepresentationValue(RepresentationInstanceList.vrABShiftTrack.ToModelRepresentation(), firstValue);
         var secondNumber = new NumericRepresentationValue(RepresentationInstanceList.vrABShiftTrack.ToModelRepresentation(), secondValue);

         firstNumber.SubtractFromSource(secondNumber);
         Assert.AreEqual(14.57, firstNumber.Value.Value);
      }
      public void GivenVariableNumberAndDoubleWhenSubtractFromSourceShouldDoThat()
      {
         var uom = _ftUnitOfMeasure.ToModelUom();
         var value = new NumericValue(uom, 24.68);
         var number = new NumericRepresentationValue(RepresentationInstanceList.vrABShiftTrack.ToModelRepresentation(), value);
         number.SubtractFromSource(10.11);

         Assert.AreEqual(14.57, number.Value.Value);
      }