21
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
The sum of two numbers is $45$. Their difference is $3$. What is the lesser of the two numbers?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
21
The sum of two numbers is $45$. Their difference is $3$. What is the lesser of the two numbers?
train