Math New Drill : SNS00-0801-L1 Numbers including 5

How many numbers of numbers which have at least one 5 in any digit in the integers from 1 to 100 are there?







Answer
19 pieces

Solution
Because the number of integers that 5 is not included in any digit at all is 9 × 9 = 81 pieces,
the number to find is 100 - 81 = 19 pieces.