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VTMO 2019 — Grade 9 — semifinal Question 8

VTMO · VTMO 2019 — Grade 9 — semifinal

Question 8

How many three-digit numbers have adjacent digits differing by at most $1$? Examples $123 , 434 , 987 , 221 , 555$.
  1. $75$
  2. $60$
  3. $90$
  4. $80$
  5. $35$