Hopefully I drew what you described.
The 6.6 represents the total of N + 3.4
We subtract the part we know from the whole /sum/total we know to get the other part.
So 6.6 - 3.4 = N
3.2 = N
The 6.6 represents the total of N + 3.4
We subtract the part we know from the whole /sum/total we know to get the other part.
So 6.6 - 3.4 = N
3.2 = N