Working systematically

Solve the equations to identify the clue numbers in this Sudoku problem.

This Sudoku problem consists of a pair of linked standard Suduko puzzles each with some starting digits

Try to solve this very difficult problem and then study our two suggested solutions. How would you use your knowledge to try to solve variants on the original problem?

Different combinations of the weights available allow you to make different totals. Which totals can you make?

Can you find the chosen number from the grid using the clues?

In how many ways can you fit two of these yellow triangles together? Can you predict the number of ways two blue triangles can be fitted together?

Using the statements, can you work out how many of each type of rabbit there are in these pens?

Use the information to describe these marbles. What colours must be on marbles that sparkle when rolling but are dark inside?

Given the products of adjacent cells, can you complete this Sudoku?

A man has 5 coins in his pocket. Given the clues, can you work out what the coins are?