Question: Break down this math problem: Lorraine and Colleen are trading stickers for buttons. Each large sticker is worth a large button or three small buttons. A small sticker is worth one small button. A large button is worth three small stickers. Lorraine starts with 30 small stickers and 40 large stickers. She trades 90% of her small stickers for large buttons. She trades 50% of her large stickers for large buttons and trades the rest of them for small buttons. How many buttons does she have by the end?
Answer: 
She trades 27 small stickers because 30 x .9 = 27
She gets 9 large buttons for these because 27 / 3 = 9
She trades 20 large stickers for large buttons because 40 x .5 = 20
She gets 20 large buttons for these because 20 / 1 = 20
She trades 50% of her large stickers for small buttons because 100 - 50 = 50
She trades 20 large stickers for small buttons because 40 x .5 = 20
She gets 60 small buttons because 20 x 3 = 60
She has 89 buttons at the end because 9 + 20 + 60 = 89