variable in matrix format, where one is dependent on all the others, Possible?

Using Mathcad Prime 8.0.
I am trying to define a variable in a matrix format, where variable has an index i= 1,2,..5.
I am able to define all variables, but cannot use a single entry, let's say d5. What is the proper way of defining my variable in such case? I tried with both matrix and table, getting same, "underdefined" fail. 

I also would like one oth the variables to depend on the others, namely l3=h-l1-l2-l4-l5(these are partial lengths of the entire hight of construction). Can one define such variables in Mathcad Prime?