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VTMO 2019 — Grade 7 — semifinal Question 13

VTMO · VTMO 2019 — Grade 7 — semifinal

Question 13

How many three-digit numbers have adjacent digits differing by $1$, such as $123 , 434 , 987$?
  1. $32$
  2. $31$
  3. $30$
  4. $33$
  5. $35$