Perhaps reading chapter with Leah upset about her sister (6)
I believe the answer is:
rachel
'her sister' is the definition.
I can't tell whether this defines the answer.
'perhaps reading chapter with leah upset' is the wordplay.
'perhaps reading' becomes 'r' ('three rs' - reading, writing, arithmetic).
'chapter' becomes 'c' (abbreviation).
'with' is a charade indicator (letters next to each other).
'upset' indicates an anagram.
'c' put after 'leah' is 'leahc'.
'leahc' with letters rearranged gives 'achel'.
'r'+'achel'='RACHEL'
'about' acts as a link.
Can you help me to learn more?
(Other definitions for rachel that I've seen before include "Import illicitly" , "Second wife of Jacob" , "Heal RC of the girl" , "Female" , "Woman" .)