Our original £100 prize crossnumber is featured on pages 34 and 35 of Issue 01.

- Download Crossnumber #1 as a PDF, or read on!

### Rules

- Although many of the clues have multiple answers, there is only one solution to the completed crossnumber. As usual, no numbers begin with 0.
- One randomly selected correct answer will win
**£100**. Three randomly selected runners up will win a Chalkdust pen. The prizes have been provided by G-Research, researchers

of financial markets and investment ideas. Find out more at gresearch.co.uk. ~~To enter, email~~**crossnumber@chalkdustmagazine.com**with the**sum of the across clues**by**22 July 2015**. Only one entry per person will be accepted. Winners will be notified by email by 1 August 2015.- Entry is now closed.

### Crossnumber

Crossnumber #1, set by Humbug:

### Clues

#### Across

- 1. D4 multiplied by D18. (10)
- 5. A multiple of 101. (3)
- 7. The difference between 10D and 11D. (10)
- 9. A palindromic number containing at least one 0. (5)
- 10. Subtract 24A multiplied by 24A backwards from 100000. (5)
- 13. Subtract 8D from 35A then multiply by 17A. (5)
- 15. Multiply this by 13D to get a perfect number. (2)
- 16. The product of two primes. (2)
- 17. A triangular number. (2)
- 19. A factor of 6D. (3)
- 20. 30A more than the largest number which cannot be written as the sum of distinct fourth powers. (7)
- 22. The sum of seven consecutive primes. (3)
- 23. When written in Roman numerals, this number is an anagram of XILXX. (2)
- 24. The largest prime factor of 733626510400. (2)
- 25. A square number. (2)
- 27. The product of all the digits of 7A. (5)
- 28. A multiple of 107. (5)
- 30. Unix time at 01:29:41 (am) on 2 January 1970. (5)
- 32. When written in a base other than 10, this number is 5331005655. (10)
- 35. The smallest number which is one more than triple its reverse. (3)
- 36. All but one of the digits of this number are the same. (10)

#### Down

- 1. 700 less than 3D. (3)
- 2. The sum of this number’s digits is equal to 16. (5)
- 3. A Fibonacci number. (3)
- 4. This is the same as another number in the crossnumber. (5)
- 5. A square number containing every digit from 0 to 9 exactly once. (10)
- 6. This number’s first digit tells you how many 0s are in this number, the second digit how many 1s, the third digit how many 2s, and so on. (10)
- 8. The lowest prime larger than 25A. (2)
- 10. The largest prime number with 10 digits. (10)
- 11. A multiple of 396533. (10)
- 12. If you write a 1 at the end of this number then it is three times larger than if you write a 1 at the start. (5)
- 13. Multiply this by 15A to get a perfect number. (2)
- 14. The factorial of 17D divided by the factorial of 16A. (7)
- 17. The answer to the ultimate question of life, the universe and everything. (2)
- 18. A multiple of 5. (5)
- 21. The number of the D clue which has the answer 91199. (2)
- 26. The total number of vertices in all the Platonic Solids (in 3D). (2)
- 27. Two more than 29D. (5)
- 29. The first and last digits of this number are equal. (5)
- 31. A multiple of 24A. (2)
- 33. Each digit of this number is a different non-zero square number. (3)
- 34. A square number. (3)