3+9, 4+8,5+7,6+6
23
1+2+3+6 is one possible answer.
Factors of 12 are: 1/12, 2/6 and 3/4. Only set which add up to 7 are 3 & 4.
when you add the numbers it will add up to a multiple of 3. Lets say 12 1+2=3 or 36 3+6=9, they are all multiples of 3.
4950
30
There are two sets of two numbers that have cubes that add up to 1729 are {1, 12} : 1³ + 12² = 1 + 1728 = 1729 {9, 10} : 9³ + 10³ = 729 + 1000 = 1729
23
1+2+3+6 is one possible answer.
48
The factor pairs of 12 are (12, 1) (6, 2) (4, 3) None of them add up to 5.
1, 2, 4, 5
1, 2 and 12 is one possible triplet.
-155
-9
23
13