Criminal can reorder key handbook for working out values (5,8)
I believe the answer is:
ready reckoner
'handbook for working out values' is the definition.
I can't tell whether this defines the answer.
'criminal can reorder key' is the wordplay.
'criminal' indicates anagramming the letters.
'can'+'reorder'+'key'='canreorderkey'
'canreorderkey' is an anagram of 'READY RECKONER'.
Can you help me to learn more?
(Other definitions for ready reckoner that I've seen before include "Book of calculation aids" , "Printed tables used in standard computations" , "Calculating aid" , "table" , "Tables of standard numerical calculations" .)