### Theory:

The greatest one-digit number is \(9\). Adding \(1\) to the greatest one-digit number will result in \(9+1 =10\). That is, it results in the smallest two-digit number.

The greatest two-digit number is \(99\). Adding \(1\) to the greatest two-digit number will result in \(99+1 =100\). That is, it results in the smallest three-digit number.

Proceeding in this way, we can have the following table.

Greatest number | Adding 1 | Smallest number |

\(9\) | \(+1\) | \(=10\) |

\(99\) | \(+1\) | \(=100\) |

\(999\) | \(+1\) | \(=1000\) |

\(9999\) | \(+1\) | \(=10000\) |

\(99999\) | \(+1\) | \(=100000\) |

\(9999999\) | \(+1\) | \(=1000000\) |

\(9999999\) | \(+1\) | \(=10000000\) |

Thus, the resultant pattern becomes.

Greatest single\((1)\) digit number \(+ 1 =\) smallest \(2\)-digit number.

Greatest \(2\)-digit number \(+ 1 =\) smallest \(3\)-digit number.

Greatest \(3\)-digit number \(+ 1 =\) smallest \(4\)-digit number.

Greatest \(2\)-digit number \(+ 1 =\) smallest \(3\)-digit number.

Greatest \(3\)-digit number \(+ 1 =\) smallest \(4\)-digit number.

and so on.