 
 <translate> Dexter have 9 x 15 = 135 basketball cards. He filled 9 - 3 = 6 plastic boxes with football cards. So, he has 6 x 20 = 120 football cards. Therefore, Dexter has 135 + 120 = 255 cards in total. The final answer: 255. <ibo> Dexter nwere 9 x 15 = kaadị bọọlụ nkata 135. O ji kaadị bọọlụ jupụta igbe plastik 9 - 3 = 6. Ya mere, o nwere 6 x 20 = 120 kaadị bọọlụ. N'ihi ya, Dexter nwere 135 + 120 = 255 kaadị n'ozuzu. Azịza ikpeazụ ya bụ: 255. 