Write figures that can be rubbed out (6)
I believe the answer is:
pencil
'write figures that' is the definition.
'pencil' can be an answer for 'write' (thesaurus). I'm unsure of the rest of the definition.
'can be rubbed out' is the wordplay.
'can' becomes 'pen' (I've seen this before).
'be rubbed out' becomes 'cil' (I can't justify this - if you can you should give a lot more credence to this answer).
'pen'+'cil'='PENCIL'
Can you help me to learn more?
(Other definitions for pencil that I've seen before include "implement in case?" , "American bureaucrat -- purple niches (anag)" , "writing equipment" , "HB writer?" , "Drawer with graphite in" .)