Question 22
Phil added consecutive numbers $1+2+3+\cdots$ on a calculator. When he pressed “=”, the display showed 198. Which number did he miss out?
Exactly one intended number is omitted; all other numbers from 1 to some final positive integer are entered once, without any other error.
Exactly one intended number is omitted; all other numbers from 1 to some final positive integer are entered once, without any other error.