Answer:
For A and B, we have (10, 6)
For C and D, we have (12, 8)
For E and F, we have (12, 8)
Step-by-step explanation:
To determine the missing numbers along each side of the triangle, we have to
*Add the two numbers at the vertex
*Subtract it from 32
*Divide it by 2
*Add 2 to it to have the 1st number
*Subtract 2 from it to have the 2nd number
So to find the pair of numbers that can be used for A and B, we'll have;

Therefore the missing numbers for A and B are 10 and 6.
So to find the pair of numbers that can be used for C and D, we'll have;

Therefore the missing numbers for C and D are 12 and 8.
So to find the pair of numbers that can be used for E and F, we'll have;

So to avoid repetition of any of the numbers between 4 and 12, we have to add and subtract 1 instead of 2.