As to your sequence, that's easy:
4+4-5+7-9=1
(I actually stopped at this topic because I had a vivid dream late in high school of which all I recalled upon waking was the phrase "4, 5, 7, 9, spetseo, spetseo, aiophilio, betseo". Weird and striking enough to stick with me for 20 years, and similar enough to your 4,4,5,7,9 sequence that I had to stop and comment. As far as I know, the "words" have no meaning or derivation. The phonology seems Greek or Russian, there's maybe some echo of the "penta-" root in "spetseo", and "bi-" in "betseo", which would yield 4,5,7,9,5,5,x,2... No idea what "aiophilio" could be. Doesn't seem to follow the pattern of the other "words" so maybe an operator?)
Anyway...
That's a very interesting dream. To remember the sequence for 20 years is pretty cool.