Number theory · Divisibility rules · Digit sums · Arithmetic mod 9
One digit of the seven-digit number \(2345678\) is to be deleted, so that the six-digit number left behind is divisible by \(9\). Which digit must it be?
- A \(8\)
- B \(7\)
- C \(6\)
- D \(5\)
- E \(4\)
Sign in to check answers, open hints, read the full solution, and track your progress. Statements are always free.
Slovenian High School Mathematics Competition for Vega Awards (MaSSA), regijsko (regional) round 2014, 1. letnik, category A, problem A1. Organized by DMFA Slovenije (Society of Mathematicians, Physicists and Astronomers of Slovenia). Source