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

A particular technique for solving Sudoku puzzles, known as "naked pair", is explained in this easy-to-read article.

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

Use the differences to find the solution to this Sudoku.

The puzzle can be solved with the help of small clue-numbers which are either placed on the border lines between selected pairs of neighbouring squares of the grid or placed after slash marks on. . . .

Two sudokus in one. Challenge yourself to make the necessary connections.

The challenge is to find the values of the variables if you are to solve this Sudoku.

This Sudoku puzzle can be solved with the help of small clue-numbers on the border lines between pairs of neighbouring squares of the grid.

This sudoku requires you to have "double vision" - two Sudoku's for the price of one

This Sudoku, based on differences. Using the one clue number can you find the solution?

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

Here is a Sudoku with a difference! Use information about lowest common multiples to help you solve it.

Two sudokus in one. Challenge yourself to make the necessary connections.

You are given the Lowest Common Multiples of sets of digits. Find the digits and then solve the Sudoku.

This Sudoku requires you to do some working backwards before working forwards.

A Sudoku based on clues that give the differences between adjacent cells.

Use the clues about the shaded areas to help solve this sudoku

Special clue numbers related to the difference between numbers in two adjacent cells and values of the stars in the "constellation" make this a doubly interesting problem.

This is a variation of sudoku which contains a set of special clue-numbers. Each set of 4 small digits stands for the numbers in the four cells of the grid adjacent to this set.

This second Sudoku article discusses "Corresponding Sudokus" which are pairs of Sudokus with terms that can be matched using a substitution rule.

A pair of Sudokus with lots in common. In fact they are the same problem but rearranged. Can you find how they relate to solve them both?

A pair of Sudoku puzzles that together lead to a complete solution.

In this Sudoku, there are three coloured "islands" in the 9x9 grid. Within each "island" EVERY group of nine cells that form a 3x3 square must contain the numbers 1 through 9.

The puzzle can be solved by finding the values of the unknown digits (all indicated by asterisks) in the squares of the $9\times9$ grid.

A Sudoku that uses transformations as supporting clues.

Four numbers on an intersection that need to be placed in the surrounding cells. That is all you need to know to solve this sudoku.

Each of the main diagonals of this sudoku must contain the numbers 1 to 9 and each rectangle width the numbers 1 to 4.

Four small numbers give the clue to the contents of the four surrounding cells.

This pair of linked Sudokus matches letters with numbers and hides a seasonal greeting. Can you find it?

We hope you enjoy being mathematically playful with these puzzling problems.

Invite your students to be playful with this selection of numerical tasks.

Activities and material for teachers.

Problems about thinking strategically for use with Stage 3 and 4 students.

Resources to accompany Charlie's presentation at the Fife Teachers' Meeting in November 2016.

Problems and toughnuts open for solution by stage 3, 4 and 5 students

Resources to accompany Fran's and Charlie's workshops at the ATM & MA Easter Conferences.

Resources to accompany NRICH team presentations at UKMT 2015 Teacher Meetings.

At the 2019 Hay Festival, Charlie Gilderdale and Alison Eves invited participants to work on a few of their favourite mathematical problems from the NRICH and RI Masterclasses collections.

Here is a list of all the secondary problems connected with Factors and Multiples

A collection of resources to support work on Factors and Multiples at Secondary level.

Resources to accompany Charlie's workshops.