a new colony was built and the builder gave contract to a sign maker to number the buildings from number 1 to 500.How many zeroes will the need?
No zero in single digit numbers
For double digit numbers:
10, 20 .. , 90 ---> 9 of them
triple digits:
using 2 zeroes: 100, 200, 300, 400, 500 --- 10 of them
using 1 zero:
case 1: the zero in 2nd place
= 5 x 1 x 9 = 45
case 2: the zero in 3rd place
= 5 x 9 x 1 = 45
total = 45+45+10+9 = 109