Generating decimal values in matlab

Question

How to generate a vector of lets say 5 decimal values such that their sum is 10.

for i=1:5
   d(i)=rand;
end

1)I know this generates the vector, but how to include the condition? 2) can I generate negative numbers as well?

Answer 1

 d = rand(5,1);
 d = d * 10 / sum(d);