If he grows 9 plants with 3 seed packets, he grows 9/3=<<9/3=3>>3 plants with 1 seed packet.

Since 1 seed packet grows 3 plants, he'll need 1 more to make the plants 12.

# Answer

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<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Carter grew 9 plants with 3 seed packets. How many more seed packets does Carter need to have a total of 12 plants in his backyard?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
1
Carter grew 9 plants with 3 seed packets. How many more seed packets does Carter need to have a total of 12 plants in his backyard?
train