Problem of the Week answers 2020

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