# Puzzles

## Archive

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#### Sunday Afternoon Maths LXVII

Coloured weightsNot Roman numerals

#### Advent calendar 2018

#### Sunday Afternoon Maths LXVI

Cryptic crossnumber #2#### Sunday Afternoon Maths LXV

Cryptic crossnumber #1Breaking Chocolate

Square and cube endings

List of all puzzles

## Tags

doubling irreducible numbers factorials triangles perimeter clocks indices calculus proportion 3d shapes games means shapes rugby factors ave square numbers graphs bases coins balancing advent cards people maths cryptic crossnumbers rectangles palindromes lines averages mean taxicab geometry shape integers ellipses geometry colouring area crosswords odd numbers squares parabolas 2d shapes algebra speed chalkdust crossnumber numbers cryptic clues money cube numbers sum to infinity integration surds probabilty hexagons sport multiplication menace circles dodecagons sums angles chocolate arrows percentages regular shapes unit fractions grids spheres crossnumbers triangle numbers chess perfect numbers christmas complex numbers remainders number prime numbers digits pascal's triangle functions division volume dice star numbers sequences routes books folding tube maps square roots planes scales quadratics differentiation time coordinates addition wordplay polygons symmetry partitions logic probability multiples fractions floors trigonometry dates## 21 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 smallest number you can make using the digits in the red boxes.

+ | ÷ | = 2 | |||

× | + | - | |||

× | - | = 31 | |||

+ | + | - | |||

- | × | = 42 | |||

= 37 | = 13 | = -2 |

## 16 December

Arrange the digits 1-9 in a 3×3 square so that the first row makes a triangle number, the second row's digits are all even, the third row's digits are all odd; the first column makes a square number, and the second column makes a cube number.
The number in the third column is today's number.

triangle | |||

all digits even | |||

all digits odd | |||

square | cube | today's number |

## 14 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.

- | + | = 10 | |||

÷ | + | ÷ | |||

÷ | + | = 3 | |||

+ | - | ÷ | |||

+ | × | = 33 | |||

= 7 | = 3 | = 3 |

## 8 December

Arrange the digits 1-9 in a 3×3 square so: each digit the first row is the number of letters in the (English) name of the previous digit, each digit in the second row is one less than the previous digit, each digit in the third row is a multiple of the previous digit; the second column is an 3-digit even number, and the third column contains one even digit.
The number in the first column is today's number.

each digit is the number of letters in the previous digit | |||

each digit is one less than previous | |||

each digit is multiple of previous | |||

today's number | even | 1 even digit |

Edit: There was a mistake in this puzzle: the original had two solutions. If you entered the wrong solution, it will automatically change to the correct one.

## 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.

+ | + | = 11 | |||

- | + | × | |||

+ | - | = 11 | |||

- | - | - | |||

+ | + | = 11 | |||

= -11 | = 11 | = 11 |

## 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 |