A letter telling my great-great-grandfather's death-day

Yesterday, while I was tidying my attic, I found a letter dedicated to my great-great-grandfather. (Note that the letter was inside a box which my great-great-grandfather transmitted to my great-grandfather, and so on...) It is supposed to tell him his death-day. I actually know he got murdered, and I also know the exact date when it happened. Now I just want to know if this letter is actually accurate, but I can't decrypt/solve it. Can someone please help me? This is what it says (except the part about how he will be killed):

... (5.3-912-83-19-24) + (2.3-12-931-453-1) = mm

(119.9-12-32-183-873) + (300-200-193-930-39.2) = dd

(4.2-342-12-123-847) + (293-1-2-93-8.7) + (59-21-329-12-23-987) + (4.2-181-192-712-9995) = yyyy

Have fun decrypting it. Meanwhile I will wait. You should start learning how to make SOS-signs, because no-one will hear you.

P.S: Don't even think of solving it the "regular" way, like you've learned in school, you silly!

• I upvoted this since it's a nice first post, but it's also very easy. Morse code is one of the first things people will look for in a cryptograms puzzle (along with Baconian cipher, turning letters into numbers, and a few other simple tricks), even without the SOS-clue; and using actual dots and dashes just makes it even more obvious. Have a look at this question for comparison. There are a lot of bright people here, so you don't have to give too many clues! I look forward to seeing more of your puzzles :-) – Rand al'Thor Aug 8 '15 at 14:10
• Also, the "..." at the start of the month line put me off a bit at first! – Rand al'Thor Aug 8 '15 at 14:23
• rand al'thor's comment will be one of the first things I look for! – Andreas Aug 9 '15 at 20:07

It was on

19 November 1901

Morse code

• Gave a lot of hints, too, such as transmitted, SOS... Great nonetheless! – Josh Aug 8 '15 at 18:55