Nell collects baseball cards. She had 43 cards. She gave 33 cards to John and yet some more to Jeff. Now she has 8 cards left. How many cards did Nell give to Jeff?
Nell has 43 cards. 
She gave 33 cards to John. 
That means she gave away 33 out of her 43 cards. 
That means 10 cards are left. 
That means she gave away 10 cards to Jeff.