How many times does the digit 9 appear in the list of all integers from 1 to 500? (The number 99, for example, is counted twice, because 9 appears two times in it.)
Here are ALL the digits from 0 to 9 in 1 to 500:
(0=91, 1=200, 2=200, 3=200, 4=200, 5=101, 6=100, 7=100, 8=100, 9=100)
1 digite numbers 1 time
2 digits up to 89 8 times
90 to 98 9 times
99 2 times
total so far is 20
100 and something 20times
200 and something 20 times
300 and something 20 times
400 and something 20 times
Total os 5*20 = 100 times
+107 
