There are 100 numbers possible between 1 and 100. There are 33 multiples of 3 between 1 and 100: $(3,6,9,\ldots,99)=(1\times 3,2\times 3,3\times 3,\ldots,33\times 3)$.  So the probability that a randomly selected number is a multiple of 3 is $\boxed{\dfrac{33}{100}}$.
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
A number is selected at random from 1 through 100, inclusive.  What is the probability that the number is a multiple of 3?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
\dfrac{33}{100}
A number is selected at random from 1 through 100, inclusive.  What is the probability that the number is a multiple of 3?
test