<|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 [15, 23, 35, 40], create an equation that equals 87. You can use basic arithmetic operations (+, -, *, /) and each number can only be used once. Show your work in <think> </think> tags. And return the final equation and answer in <answer> </answer> tags, for example <answer> 15 + 23 = 38, 38 + 40 = 78, 78 - 23 = 55, 55 + 35 = 90, 90 + 23 = 113, 113 - 23 = 90, 90 - 35 = 55, 55 + 15 = 70, 70 + 35 = 105, 105 - 15 = 90, 90 - 35 = 55, 23 + 15 = 38, 38 - 15 = 23, 23 - 40 = -17, -17 - 23 = -40, 15 + 23 = 38, 38 + 40 = 78, 78 - 23 = 55, 55 + 15 = 70, 70 - 35 = 35, 35 + 23 = 58, 58 + 77 = 135 - 48 = 87 </answer>.<|im_end|>
<|im_start|>assistant
Let me solve this step by step.
<think>