<|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 [28, 84, 65, 30], craft an equation that equals 31. Employ basic arithmetic operations (+, -, *, /) and use each number only once. Present your work in <think> </think> tags. Afterwards, provide the final equation and solution in <answer> </answer> tags, akin to <answer> (1 + 2) * 3 = 9 </answer>, where 9 is an example. <|im_end|>
<|im_start|>assistant
Let me solve this step by step.
<think>