Almost left out the scripture tying it together, Daniel 9:26 and 27, which I suggest you look in several bibles and interlinear translations, but it says in NWT this key phrase, (but the whole thing important to understand, and look in several translations), "he must keep the covenant in force for the many for one week; and at the half of the week (3.5 days, time times and 1/2 time, 42 months, 1260 days), he will cause sacrifice and gift offering to ceease. "and upon the wing of disgusting things there will be the one causing desolation; and until an exterminatio, the very thing decided upon will go pouring out also upon the one lying desolate."
NOW again look at Daniel 12:11 - "and from the time that the constant feature has been removed (daily sacrifice and gift offerings of Daniel 9:26,27) and there has been a placing of the disgusting thing causing desolation (that which is making worship unacceptable to God and desolate), there will be one thousand two hundred and ninety days. ) The 2nd half of the week of Daniel 9:26,27 and hence why also those extra 30 days. THEN after that week is over, when the WILD BEAST is in full power, why Daniel 11:12 says "Happy is the one who is keeping in expectation arrives at the one thousand three hundred and thirty five days!" Which means at the conclusion of this week, there is 45 days (from the scripture, actual time length is another matter).
I went beyond what I wanted to show, but I feel at ease showing this right now, so if anyone gets anything interesting out of this, or if any understanding of other things through this, please let me know.