Also known as:
A kriss kross or fitword with numbers instead of letters.
As with a kriss kross, a good place to start solving the puzzle is with those number-lengths that appear the least frequently. Filling the grid is a process of logic, often involving thinking ahead several moves to deduce which of several possible numbers is the correct one to fill any given space.
The puzzle compiler must take care to ensure that there is only one possible solution.