Both the East and West metaphysical community believes that symbols and numbers carries vibration and energy.
For the Fengshui system, numbers are representative of elements as well. However from what I observed, not many practitioners are into adopting numbers for their Fengshui planning.
It may be more relevant in the past when there are not as many things found in a house.
Contemporary house has problems with too much clutter. If numbers are adopted, it is usually done in a very subtle way.
Fengshui numbers can be related to floor numbers. However there is no consensus on how to use it properly.
e.g. if the floor number is double digit, e.g. 28. Do you use the end number 8 or do you 2+8=10, 1+0= 1 and use the number 1 instead.
Could be due to the lack of consensus that numbers are not employed in a big way for Fengshui work.
1, 6 = Water element.
2, 7 = Fire element.
3, 8 = Wood element.
4, 9 = Metal number
This is based on the 河图, 洛书 legend, where the mystical fire horse and dark turtle emerges from nature, carrying strange “codes” , almost like binary codes on their outer skin and turtle shell.