My dearest Wildcat,
9 is not useful. It is merely the result. Knowing that 1+1=2 does not make 2 useful it merely makes it the result of the sum.
Ti + Fe does not equal 9. It only equals Ti + Fe. 1+8=9 but what does that mean? Sure knowing the opposites and such helps in sorting out the standard order of the archetypical person of that type but firstly you'd have to know what is opposite to what and then do the math... it'd be easier to lit the first four in order of importance and the write their opposites next to them in another column. Then you simply read down column one and up column two. No numbers.. no math.. simple.