# Mathematics

##### Across
1. 3. Numeral system which uses 0-9 and A-F
2. 9. Six-sided polygon
3. 12. Numbers 2,13,57 are all ________
4. 13. Greek letter used to represent a sum in a series
5. 15. repeated exponentiation
6. 16. Platonic solid with the most (20) faces
7. 18. Simplest platonic solid, also known as a triangular pyramid
8. 23. Statement thought to be true but which proof is not yet known
9. 25.
10. 26. Symbol used for the roots of numbers
11. 28. The square root of -1 is ______
12. 29. The Pythagoreans believed that all even numbers are _______
13. 30. Arabic numbers were invented in _______
##### Down
1. 1. The Abel-Ruffini theorem states a formula for solving _______ functions cannot exist
3. 4. Founder of set theory
4. 5. This polygon cannot be constructed with a compass and a ruler
5. 6. Ten to the power of hundred
6. 7. The ______ conjecture is the only Millenium Prize Problem solved so far. It was solved in 2003 by Grigori Perelman, who later declined the \$1,000,000 prize money.
7. 8. Famous philosopher, who invented the convention of representing unknowns in equations by x and y
8. 10. By gluing together two sides of a tape you get a one sided surface named the _______ strip
9. 11. This number has no roman numeral representation
10. 14. In _____ arithmetic numbers "wrap around" when reaching a certain value. It is often called clock arithmetic.
11. 17. Statement assumed to be true
12. 19. Field of mathematics in which a donut and a cup are considered equal
13. 20. The plus sign (+) originally stood for this Latin word
14. 21. Less than zero
15. 22. Written at the end of a proof
16. 24. Earliest known mathematician
17. 27. Lemniscate is the shape of what mathematical symbol?
18. 29. Number of colours required to colour any map so that no adjacent regions have the same colour