2 Tables with different Keys to sum in the rows - how to get an common summary about both tables?

[Mvvv]

Hi,
it's difficult to explain and I think to understand, so I made screenshots.

The first table has Codes in it, the second too. There a different code variantes that have to summarize, but let's look only the my example now. Here I explan with aa, ab and ac Codes. The ab and ac Codes are only in Table 1. 

For my final summarize I need all values from Table 1, which have the same Nr and the code must be aa, ab or ac. In Table 2 there exists only Code aa.
So if I make a summarize now. I have data in Column aa for both tables, but only for ab and ac in Table1 Colums.
At the end, I need only a summarize Column for Code aa, ab and ac togehter, with the sum of all from Table 1 and the sum of all from aa Code table 2.

What could be the best idea to solve this?

I tried a lot, with helping tables and complicates Power Query M Codes, but I never get the wanted result. I think maybe I can't see clear anymore about that one whole day problem now. I hope someone has a maybe "easy" solution?

Best thanks in advance.

[Mvvv]

O.K. I found a solution after a night of sleep. I used search and replace and replaced as example, all ab and ac with aa.
I'm still interessted in better suggestions.