Working systematically

problem
Negative dice

Age

11 to 14

Challenge level

If the odd numbers on two dice are made negative, which of the totals cannot be achieved?
problem
Nine, ten and one

Age

11 to 14

Challenge level

Can you find the value of t in these equations?
problem
Spot the card

Age

14 to 16

Challenge level

It is possible to identify a particular card out of a pack of 15 with the use of some mathematical reasoning. What is this reasoning and can it be applied to other numbers of cards?
problem
Arrangements

Age

7 to 11

Challenge level

Is it possible to place 2 counters on the 3 by 3 grid so that there is an even number of counters in every row and every column? How about if you have 3 counters or 4 counters or....?
problem
Patchwork quilt

Age

7 to 14

Challenge level

Squares of the type shown are sewn together to make a quilt. How many different quilts can be made?
problem
Wallpaper Sudoku

Age

11 to 16

Challenge level

A Sudoku that uses transformations as supporting clues.
problem
Diagonal product Sudoku

Age

11 to 16

Challenge level

Given the products of diagonally opposite cells - can you complete this Sudoku?
problem
Diagonal sums Sudoku

Age

7 to 16

Challenge level

Solve this Sudoku puzzle whose clues are in the form of sums of the numbers which should appear in diagonal opposite cells.
problem
Making 11p

Age

11 to 14

Challenge level

How many ways are there to make 11p using 1p, 2p and 5p coins?
problem
Fly away

Age

11 to 14

Challenge level

Can you work out the values of the digits in this addition sum?