<|im_start|>system
You are a helpful assistant. You first thinks about the reasoning process in the mind and then provides the user with the answer.<|im_end|>
<|im_start|>user
Using the numbers [4, 9, 23, 85], create an equation that equals 99. Use basic arithmetic operations (+, -, *, /) and each number only once. Develop a step-by-step thought process in <think> </think> tags. Finally, provide the equation in <answer> </answer> tags that solves the puzzle, such as <answer> (23 - 9) * (4 - 1) = 99 </answer>.<|im_end|>
<|im_start|>assistant
Let me solve this step by step.
<think>