# Puzzles

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#### Advent calendar 2017

#### Sunday afternoon maths LXII

What's the star?#### Sunday afternoon maths LXI

XYZ#### Sunday afternoon maths LX

Where is Evariste?Bending a straw

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time geometry 2d shapes 3d shapes numbers spheres trigonometry complex numbers algebra lines graphs coordinates odd numbers fractions differentiation calculus folding tube maps ellipses triangle numbers money bases triangles squares area square numbers chess probability circles averages speed sport multiples dates factors parabolas functions logic cards games people maths shape prime numbers irreducible numbers probabilty angles proportion dice integration sum to infinity dodecagons hexagons multiplication factorials coins shapes regular shapes colouring grids floors integers rugby crosswords percentages digits sums christmas rectangles clocks menace routes taxicab geometry remainders chalkdust crossnumber palindromes sequences means unit fractions division square roots surds doubling quadratics indices planes volume number partitions ave pascal's triangle mean advent symmetry arrows addition cube numbers star numbers perfect numbers## 19 December

Put the digits 1 to 9 (using each digit exactly once) in the boxes so that the products are correct. Today's number is the smallest number that can be made using the digits in the red boxes.

× | × | = 90 | |||

× | × | × | |||

× | × | = 84 | |||

× | × | × | |||

× | × | = 48 | |||

= 64 | = 90 | = 63 |

## 17 December

Arrange the digits 1-9 in a 3×3 square so that every row makes a three-digit square number, the first column makes a multiple of 7 and the second column makes a multiple of 4.
The number in the third column is today's number.

square | |||

square | |||

square | |||

multiple of 7 | multiple of 4 | today's number |

## 12 December

Put the digits 1 to 9 (using each digit exactly once) in the boxes so that the sums are correct. Today's number is the product of the numbers in the red boxes.

+ | + | = 17 | |||

+ | + | + | |||

+ | + | = 7 | |||

+ | + | + | |||

+ | + | = 21 | |||

= 11 | = 20 | = 14 |

## 3 December

Put the digits 1 to 9 (using each digit exactly once) in the boxes so that the sums are correct. The sums should be read left to right and top to bottom ignoring the usual order of operations. For example, 4+3×2 is 14, not 10. Today's number is the product of the numbers in the red boxes.

+ | + | = 17 | |||

+ | ÷ | × | |||

÷ | - | = 1 | |||

- | × | ÷ | |||

÷ | - | = 0 | |||

= 4 | = 12 | = 27 |

## 16 December

Put the digits 1 to 9 (using each digit exactly once) in the boxes so that the sums are correct. The sums should be read left to right and top to bottom ignoring the usual order of operations. For example, 4+3×2 is 14, not 10.
Today's number is the largest number than can be made from the digits in red boxes.

× | × | = 6 | |||

× | × | × | |||

× | × | = 180 | |||

× | × | × | |||

× | × | = 336 | |||

= 32 | = 70 | = 162 |

## 13 December

Put the digits 1 to 9 (using each digit exactly once) in the boxes so that the sums are correct. The sums should be read left to right and top to bottom ignoring the usual order of operations. For example, 4+3×2 is 14, not 10. Today's number is the smaller number in a red box to the power of the larger number in a red box.

+ | - | = 8 | |||

- | - | - | |||

+ | ÷ | = 3 | |||

+ | ÷ | × | |||

+ | × | = 120 | |||

= 8 | = 1 | = 8 |

## 7 December

Put the digits 1 to 9 (using each digit once) in the boxes so that the three digit numbers formed (reading left to right and top to bottom) have the desired properties written by their rows and columns.

multiple of 25 | |||

today's number | |||

all digits even | |||

multiple of 91 | multiple of 7 | cube number |

## 4 December

Put the digits 1 to 9 (using each digit exactly once) in the boxes so that the sums are correct. The sums should be read left to right and top to bottom ignoring the usual order of operations. For example, 4+3×2 is 14, not 10. Today's number is the product of the digits in the red boxes.

+ | ÷ | = 2 | |||

+ | ÷ | - | |||

÷ | - | = 5 | |||

÷ | - | × | |||

- | × | = 4 | |||

= 3 | = 5 | = 6 |