Only "7","0","+"allowed
Logic
Level
3
A malfunction calculator can only perform calculation using \("7", "0"\) and \("+"\) keys. That means number such as \("77707"\) could still be keyed-in for the addition operation. What is the least number of times that the \("7"\) key must be used in the addition process to view \("222222"\) on its screen?
by
Peng Ying Tan