How many times does the digit 9 appears from 1 to 1000?

The answer is ‎300.

(9,19,29,39,49,59,69,79,89,90,91,92,93,94,95,96,97,98,99) = 20

20*10 (ten hundreds) = 200

Add another 100 for the nine hundred (from 900 to 999)

200+100 = 300