Answers: Week of November 30th
Problem #1: How many two digit numbers are there (i.e. between 10 and 99) where the sum of that number’s digits is also a two digit number? (for example, 87 would be 8+7=15)
Answer: 45
Problem #2: (hard) How many three-digit numbers are there where the sum of that number’s digits is a two-digit number?
Answer: 735