We look first for the total number of books that were sold: 60 + 10 + 20 + 44 + 66 = <<60+10+20+44+66=200>>200 books.

So the total number of books that were not sold is: 800 – 200 = <<800-200=600>>600 books.

# Answer

600
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Ali had a stock of 800 books in his Room. He sold 60 on Monday, 10 on Tuesday, 20 on Wednesday, 44 on Thursday and 66 on Friday. How many books were not sold?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
600
Ali had a stock of 800 books in his Room. He sold 60 on Monday, 10 on Tuesday, 20 on Wednesday, 44 on Thursday and 66 on Friday. How many books were not sold?
train