If Audrey was asleep for 10 hours last night and dreamed for 2/5 of the time, she dreamed for 2/5*10 = <<10*2/5=4>>4 hours.

The total time Audrey slept without dreaming is 10-4 = <<10-4=6>>6 hours.

# Answer

6
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Audrey was asleep for 10 hours last night and dreamed for 2/5 of the time. How much of the night was she not dreaming?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
6
Audrey was asleep for 10 hours last night and dreamed for 2/5 of the time. How much of the night was she not dreaming?
train