The books will cost $40 because 8 x 5 = <<8*5=40>>40

He needs to save up $27 because 40 - 13 = <<40-13=27>>27

# Answer

27
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Tommy wants to earn enough money to buy 8 new books. Each book costs $5. If Tommy already has $13, how much does he need to save up?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
27
Tommy wants to earn enough money to buy 8 new books. Each book costs $5. If Tommy already has $13, how much does he need to save up?
train