Worries about first twenty Russian coins (8)
I believe the answer is:
troubles
'worries about first twenty russian coins' is the definition.
'troubles' can be an answer for 'worries' (I've seen this before). I am not sure about the 'about first twenty russian coins' bit.
'worries about first twenty russian coins' is the wordplay.
'worries' becomes 'o' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'about' means one lot of letters goes inside another.
'first twenty' becomes 't' (ost letter of 'twenty').
'russian coins' becomes 'rubles' (I've seen this in another clue).
't'+'rubles'='trubles'
'o' placed into 'trubles' is 'TROUBLES'.
Can you help me to learn more?
(Other definitions for troubles that I've seen before include "Pack them up in your old kit bag and smile" , "Inconveniences, perturbs" , "Old song: 'Pack up your . . . . . . . . In your old kit bag'" , "Problems and difficulties - subtle or what?" , "Distressing or painful events" .)