Duck number

A kind of number

About Duck number

A duck number is a positive integer that contains the digit 0 but does not start with 0. So 10, 20, 101, 102 are duck numbers; 0 and 7 are not.

Key features

  • Used in some programming exercises and number puzzles.
  • All such numbers have at least two digits.

Examples:

10, 20, 101, 102, 201, 1001

Further reading