Numberless problems are a brilliant idea.  So many children have difficulty solving problems with words.  So the trick is to take the numbers out so that you only have the words.  That lets everyone focus on how the words work without the numbers getting in the way.

Once you have discussed the problem together and visualised what is happening, you then 

• create an appropriate diagram 
• put some simple numbers into the problem
• work together to solve it.

Once the problem has been solved with simple numbers, then more challenging numbers can be tried.

Once sufficient pupils are secure in the thinking, groups of children can use

• Plan Together (agree an appropriate diagram to model the problem and numbers to put into it)
• Work Apart (solve the agreed problem individually) 
• Check Together (compare answers and inspect errors)