Centimetres is not a measure of mass. Could you re-phrase your question?
If Widget A weighs 100 cubic inches in volume and Widget B weighs 50 cubic inches in volume.
Is it true that
Widget A is 100% more bigger than Widget B.
Yet widget B is only 50% smaller than Widget A.
I'm asking because me and someone are having an argument if that is true. I don't think it is.
In the first statement widget B is the reference point and so widget A is 100% (50 in³) bigger than widget B.
In the second statement widget A is the reference point and 50 in³ is 50% of 100in³.
Therefore the pair of statements is true