Join the USAMO Guide Discord Server. Regular updates are posted there!
From module Arithmetic and Number Theory Basics
Find the sum of the digits in the answer to 999…99⏟94 nines×444…44⏟94 fours\underbrace{999\dots99}_{94\text{ nines}} \times \underbrace{444\dots44}_{94\text{ fours}}94 nines999…99×94 fours444…44 where a string of 949494 nines is multiplied by a string of 949494 fours.
Select an answer
← Back to all problems