Dividing a number into random unequal parts

Generate 12 random numbers from your favourite random number generator, call them r1..r12.

Add them all up, call the sum sum.

Your first random fraction of 4 is (r1/sum)*4. The rest should be obvious.

Generate any random number greater than 1 and after rescale to required sum.

Example:

• Required sum: 4
• Random Numbers: 1 2 3 4 5 6 7 8 9 10 11 12
• Sum = 78
• Rescaled numbers:

1 rescaled to (1*4) / 78

2 rescaled to (2*4) / 78

...

12 rescaled to (12*4) / 78