Provide your best answer for the following math problem. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The problem is: how many times digit 6 is used while writing numbers from 150 to 1000 ?
252
150 has 1 six, 260 has 6 sixes, 3600 has 30 sixes