First find the number of matches the dog eats: 10 matches * 2 = <<10*2=20>>20 matches

Then subtract all the lost matches from the starting number to find the final number: 70 matches - 10 matches - 20 matches = <<70-10-20=40>>40 matches

# Answer

40
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Nate starts his camping trip with 70 matches. He drops 10 in a creek and his dog eats twice as many. How many matches does he have left?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
40
Nate starts his camping trip with 70 matches. He drops 10 in a creek and his dog eats twice as many. How many matches does he have left?
train