Blue_Orb
Beginning
There are three prime numbers in the range 1-6 and three spots in row F on the right half of the board. Therefore, F4, F5, and F6 must all contain prime numbers. The three numbers in F3, F4, and F5 must be distinct, because they are all in the same row. There are three possible combinations of three distinct numbers that add up to 12: 1, 5, 6; 2, 4, 6; and 3, 4, 5. The only one of these combinations that contains two prime numbers is 3, 4, 5. Therefore, F4 and F5 must contain a 3 and a 5 (though we don’t know which is which yet), so F3 has to contain a 4. Moreover, F6 must contain a 2 because it is the last remaining prime number that has not been accounted for.
Beginning
There are three prime numbers in the range 1-6 and three spots in row F on the right half of the board. Therefore, F4, F5, and F6 must all contain prime numbers. The three numbers in F3, F4, and F5 must be distinct, because they are all in the same row. There are three possible combinations of three distinct numbers that add up to 12: 1, 5, 6; 2, 4, 6; and 3, 4, 5. The only one of these combinations that contains two prime numbers is 3, 4, 5. Therefore, F4 and F5 must contain a 3 and a 5 (though we don’t know which is which yet), so F3 has to contain a 4. Moreover, F6 must contain a 2 because it is the last remaining prime number that has not been accounted for.