Our original prize crossnumber is featured on pages 36 and 37 of Issue 16.

- Download Crossnumber #16 as a PDF, or read on!
- Submit your answer

### Corrections

**There was a typo in the clue for 1D: This originally read “One less than 1D”, when it should have been “One less than 1A.**. This has been corrected below and in the pdf linked above.

### Rules

- Four of the across clues and four of the down clues are false. All the other clues are true.
- Solvers may wish to use the OEIS, Wikipedia, Python, a slide rule, etc to (for example) obtain a list of cube numbers, but no programming should be necessary to solve the puzzle. As usual, no numbers begin with 0.
- One randomly selected correct answer will win a
**£100 Maths Gear goody bag**, including non-transitive dice, a*Festival of the Spoken Nerd*DVD, and much, much more. Three randomly selected runners up will win a Chalkdust T-shirt. Maths Gear is a website that sells nerdy things worldwide, with free UK shipping. - To enter, submit the
**sum of all the digits in the row marked by arrows**using this form by**14 April 2023**. Only one entry per person will be accepted. Winners will be notified by email and announced on our blog by 1 May 2023.

### Crossnumber

Crossnumber #16, set by Humbug:

### Across clues

(four of these clues are false)

- 1. One less than 1D. (3)
- 3. A multiple of 11111. (5)
- 6. Each digit of this number (excluding the first) is one less than the previous digit. (3)
- 8. A multiple of 111. (3)
- 9. 111 more than 8A. (3)
- 10. The highest common factor of 48A and this number is 6. (3)
- 12. An even number. (3)
- 14. Two times 4D. (2)
- 16. A factor of 19A. (2)
- 17. The sum of this number’s digits is 11. (4)
- 19. Greater than 1A. (3)
- 21. The sum of this number’s digits is 13. (4)
- 23. A square number. (2)
- 25. One quarter of 23A. (2)
- 26. Two times 28A. (2)
- 27. The product of 24D and 25D. (5)
- 28. Not a prime number. (2)
- 29. Each digit of this number is a factor of 38D. (2)
- 30. One quarter of 29A. (2)
- 32. An anagram of 17A. (4)
- 34. 15 less than 10A. (3)
- 36. An anagram of 21A. (4)
- 38. A multiple of 3 whose final digit is the same as the final digit of 12A. (2)
- 39. A square number. (2)
- 41. Two times 41D. (3)
- 43. The sum of this number’s digits is 10. (3)
- 45. Two times 47A. (3)
- 47. A multiple of 9. (3)
- 48. Two times 42D. (3)
- 49. A multiple of 11111. (5)
- 50. A multiple of 55. (3)

### Down clues

(four of these clues are false)

- 1. One less than 1A. (3)
- 2. Two times 10A. (3)
- 3. Two times 38D. (4)
- 4. A factor of 1A. (2)
- 5. Two times 1D. (4)
- 6. Two times 7D. (3)
- 7. A prime number. (3)
- 11. Two times 13D. (3)
- 13. A multiple of 111. (3)
- 15. Two times 14A. (2)
- 16. A number with four distinct prime factors. (2)
- 17. A multiple of 11111. (5)
- 18. A square number. (2)
- 20. The product of 19A and 34A. (5)
- 21. Five more than 29D. (2)
- 22. A multiple of 11111. (5)
- 24. 30 more than than 6D. (3)
- 25. A prime number. (3)
- 29. Five more than 21D. (2)
- 31. A factor of 25D. (2)
- 33. Two times 11D. (3)
- 34. A factor of an anagram of 6D. (2)
- 35. Greater than 15D. (2)
- 37. Two times 33D. (3)
- 38. Two times 3D. (4)
- 40. A multiple of 1111. (4)
- 41. Two times 48A. (3)
- 42. Two times 41A. (3)
- 43. A multiple of 55. (3)
- 44. A number less than 200. (3)
- 46. The sum of the digits in the row marked by arrows. (2)