A street has 50 houses on each side, for a total of 100 houses. The addresses on the south side of the street form an arithmetic sequence, as do the addresses on the north side of the street. On the south side, the addresses are 1, 5, 9, etc., and on the north side they are 3, 7, 11, etc. A sign painter paints house numbers on a house for $\$1$ per digit. If he paints the appropriate house number once on each of these 100 houses, how much does he earn?
You need 100 ODD numbers 1 - 199
1 3 5 7 9 and then 2-digit ones 11-99 then 3 digit ones 101-199
5 90 150 = 145 digits (I think !)