Kelly has 10 nintendo games. She found 21 more nintendo games. How many does she need to give away so that she will have 4 games left?
Kelly has 10 games. 
She found 21 more games. 
That means she has a total of 31 games. 
She wants to give away games until she only has 4 games left. 
That means she wants to give away 27 games.