Difficulties grasping one thousand plus eight, maybe a mental block? (6,4)
I believe the answer is:
rubiks cube
'a mental block?' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'difficulties grasping one thousand plus eight maybe' is the wordplay.
'difficulties' becomes 'rubs' (rub is a kind of difficulty).
'grasping' is an insertion indicator (inserted letters are held or grasped).
'one thousand plus' becomes 'ik' (I can't justify this - if you can you should believe this answer much more).
'eight maybe' becomes 'cube' (eight is two cubed).
'rubs' enclosing 'ik' is 'rubiks'.
'rubiks'+'cube'='RUBIKS CUBE'
Can you help me to learn more?
(Another definition for rubiks cube that I've seen is " 3-D combination puzzle invented in 1974".)