YESTERDAY’S WORD SLEUTH ANSWER

THE FIFTIES TODAY’S STICKELERS ANSWER

The answer for the range 0 - 9 is 1, which can readily be seen. Let’s take a look at all the fives from 1-100. The range 0-9 repeats 10 times, once for each leading digit, and each time this happens it increases the number of 5’s by 1. However, when the leading digit is 5, we have to add an additional 10 to the number of 5’s (because of 50, 51, 52, ...). This gives us a total of (1)(10) + 10 = 20. Similarly, the answer for the range 000 to 999 is (20)(10) + 100 = 300, and the answer for the range 0000 to 9999 is (300)(10) + 1000 = 4000.