To solve this puzzle, you must:
Find synonyms of the words in each 'word sum', where the letters of those on the left can be combined and anagrammed to make a synonym of the word on the right (or - in one case - the word itself).
Like so...
not left + up = honest
RIGHT + UP --> UPRIGHT
tear + boy = jail
RIP + SON --> PRISON
five + I = kiln
V + ONE --> OVEN (using Roman numerals)
recursion + maize + confident = recursion
I + CORN + SURE --> RECURSION (where 'I' is an example of 'recursion' where one is referencing themselves with a pronoun)
uncommon/back + rage/span = anagram
RARE/REAR + ANGER/RANGE --> REARRANGE