# Blog

## Archive

Show me a random blog post**2019**

### Jun 2019

Proving a conjecture### Apr 2019

Harriss and other spirals### Mar 2019

realhats### Jan 2019

Christmas (2018) is over**2018**

**2017**

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mathslogicbot rugby matt parker draughts christmas books approximation sorting probability error bars mathsjam electromagnetic field curvature sound christmas card fractals rhombicuboctahedron manchester science festival folding paper asteroids php gerry anderson games london graph theory golden ratio reuleaux polygons inline code chalkdust magazine dragon curves polynomials triangles puzzles hexapawn chess radio 4 harriss spiral martin gardner the aperiodical wool pac-man pythagoras trigonometry menace propositional calculus dataset cross stitch geometry craft dates logic game show probability interpolation golden spiral sport frobel video games weather station light binary reddit ternary oeis noughts and crosses latex flexagons statistics palindromes london underground accuracy arithmetic aperiodical big internet math-off data royal baby nine men's morris estimation misleading statistics stickers manchester countdown final fantasy bubble bobble bodmas pizza cutting python map projections european cup world cup braiding national lottery hats raspberry pi folding tube maps people maths tennis news football programming realhats a gamut of games mathsteroids plastic ratio speed javascript coins platonic solids go captain scarlet game of life twitter machine learning chebyshev## Christmas card 2017

**2017-12-18**

Just like last year, TD and I spent some time in November this year designing a puzzle Christmas card for Chalkdust.

The card looks boring at first glance, but contains 10 puzzles. Converting the answers to base 3, writing them in the boxes on the front, then colouring the 1s black and 2s orange will reveal a Christmassy picture.

If you want to try the card yourself, you can download this pdf. Alternatively, you can find the puzzles below and type the answers in the boxes. The answers will be automatically converted to base 3 and coloured...

# | Answer (base 10) | Answer (base 3) | ||||||||

1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||

2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||

3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||

4 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||

5 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||

6 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||

7 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||

8 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||

9 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||

10 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

- In a book with 116 pages, what do the page numbers of the middle two pages add up to?
- What is the largest number that cannot be written in the form \(14n+29m\), where \(n\) and \(m\) are non-negative integers?
- How many factors does the number \(2^6\times3^{12}\times5^2\) have?
- How many squares (of any size) are there in a \(15\times14\) grid of squares?
- You take a number and make a second number by removing the units digit. The sum of these two numbers is 1103. What was your first number?
- What is the only three-digit number that is equal to a square number multiplied by the reverse of the same square number? (The reverse cannot start with 0.)
- What is the largest three-digit number that is equal to a number multiplied by the reverse of the same number? (The reverse cannot start with 0.)
- What is the mean of the answers to questions 6, 7 and 8?
- How many numbers are there between 0 and 100,000 that do not contain the digits 0, 1, 2, 3, 4, 5, or 6?
- What is the lowest common multiple of 52 and 1066?

### Similar posts

Christmas card 2016 | Christmas card 2018 | Christmas (2018) is over | Christmas (2018) is coming! |

### Comments

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**2018-01-01**

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2019-01-0410,000and 100,000 that do not contain the digits 0, 1, 2, 3, 4, 5, or 6.Matthew