More generally, when you are doing modulus arithmetic, specifically mod 12.
ie.
(9+4) mod 12 = 1
not as tough as 9 pm + 4 hours = 1 am
42
19
1 plus 1 equals one fact
(-1,-2)
(-4, -1)
4 + 4 + 1 = 9
4+1=5. Plus 4 equals 9. Plus 77685769844446473 equals 77685769844446482. Plus 3 equals 77685769844446485. Plus 8 equals 77685769844446493. Plus 1 equals 77685769844446494. Plus 9870998342523322424 equals 1064785604097768918. Plus 4 equals 1064785604097768922.
-13
42
s=4
19
1 plus 1 equals one fact
(-1,-2)
(-4, -1)
5. Just do 9 minus 4. 5 plus 4 equals 9
4/9 + 2/9 + 1/9 = 7/9
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