She previously had 2 cartons + 7 cartons = <<2+7=9>>9 cartons of berries.

Emilia needs to buy 42 cartons - 9 cartons = <<42-9=33>>33 cartons of berries.

# Answer

33
<|im_start|>system
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<|im_start|>user
Emilia needs 42 cartons of berries to make a berry cobbler. She already has 2 cartons of strawberries and 7 cartons of blueberries in her cupboard. She decides to go to the supermarket to get more cartons. How many more cartons of berries should Emilia buy?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
33
Emilia needs 42 cartons of berries to make a berry cobbler. She already has 2 cartons of strawberries and 7 cartons of blueberries in her cupboard. She decides to go to the supermarket to get more cartons. How many more cartons of berries should Emilia buy?
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