Put the numbers indicated in the grid, one number per square. Each number must be horizontally, vertically, or diagonally adjacent to the number before it. No two numbers in the same row or column can have a sum that ends in zero. Some numbers in each puzzle have been given to get you started.

Numbers 1-9: | 1. | 2. | 3. | 4. | 5. |

Numbers 1-12: | 6. | 7. | 8. | 9. | 10. |

11. | 12. | 13. | 14. | 15. |

Numbers 1-16: | 16. | 17. | 18. | 19. | 20. |

21. | 22. | 23. | 24. | 25. |

The solutions are here.