user: ### NOW ANSWER:
Question: What is the size difference for exa?
Columns: ['Symbol', 'Prefix', 'SI Meaning', 'Binary meaning', 'Size difference']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['K', 'kilo', '10 3 = 1000 1', '2 10 = 1024 1', '2.40%']
SQL:

assistant: SELECT "Size difference" FROM "Table" WHERE "Prefix" = 'exa';