Kid from second marriage with learners writes off car (6)
I believe the answer is:
totals
'learners writes off car' is the definition.
I can't tell whether this defines the answer.
'kid from second marriage' is the wordplay.
'kid' becomes 'tot' (tot is a kind of kid).
'from' means one lot of letters go next to another.
'second marriage' becomes 'als' (I can't explain this - if you can you should give a lot more credence to this answer).
'tot'+'als'='TOTALS'
'with' is the link.
Can you help me to learn more?
(Other definitions for totals that I've seen before include "Sums and aggregates" , "Kills" , "Adds up the entire amounts" , "Aggregations or sums" .)