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

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An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

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Three children are going to buy some plants for their birthdays. They will plant them within circular paths. How could they do this?

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This challenge extends the Plants investigation so now four or more children are involved.

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The letters of the word ABACUS have been arranged in the shape of a triangle. How many different ways can you find to read the word ABACUS from this triangular pattern?

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This challenging activity involves finding different ways to distribute fifteen items among four sets, when the sets must include three, four, five and six items.

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Investigate the different ways that fifteen schools could have given money in a charity fundraiser.

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A few extra challenges set by some young NRICH members.

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

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

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The items in the shopping basket add and multiply to give the same amount. What could their prices be?

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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.

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

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The clues for this Sudoku are the product of the numbers in adjacent squares.

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Place the 16 different combinations of cup/saucer in this 4 by 4 arrangement so that no row or column contains more than one cup or saucer of the same colour.

Find out about Magic Squares in this article written for students. Why are they magic?!

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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.

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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. . . .

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Mr McGregor has a magic potting shed. Overnight, the number of plants in it doubles. He'd like to put the same number of plants in each of three gardens, planting one garden each day. Can he do it?

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Ben, Jack and Emma passed counters to each other and ended with the same number of counters. How many did they start with?

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There are nine teddies in Teddy Town - three red, three blue and three yellow. There are also nine houses, three of each colour. Can you put them on the map of Teddy Town according to the rules?

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

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

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Rather than using the numbers 1-9, this sudoku uses the nine different letters used to make the words "Advent Calendar".

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Play the divisibility game to create numbers in which the first two digits make a number divisible by 2, the first three digits make a number divisible by 3...

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A monkey with peaches, keeps a fraction of them each day, gives the rest away, and then eats one. How long can his peaches last?

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

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

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Use the differences to find the solution to this Sudoku.

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A cinema has 100 seats. Show how it is possible to sell exactly 100 tickets and take exactly Â£100 if the prices are Â£10 for adults, 50p for pensioners and 10p for children.

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60 pieces and a challenge. What can you make and how many of the pieces can you use creating skeleton polyhedra?

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The number of plants in Mr McGregor's magic potting shed increases overnight. He'd like to put the same number of plants in each of his gardens, planting one garden each day. How can he do it?

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Replace the letters with numbers to make the addition work out correctly. R E A D + T H I S = P A G E

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A student in a maths class was trying to get some information from her teacher. She was given some clues and then the teacher ended by saying, "Well, how old are they?"

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Gabriel multiplied together some numbers and then erased them. Can you figure out where each number was?

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By selecting digits for an addition grid, what targets can you make?

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In this game you are challenged to gain more columns of lily pads than your opponent.

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Can you use your powers of logic and deduction to work out the missing information in these sporty situations?

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A challenging activity focusing on finding all possible ways of stacking rods.

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

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This cube has ink on each face which leaves marks on paper as it is rolled. Can you work out what is on each face and the route it has taken?

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Five numbers added together in pairs produce: 0, 2, 4, 4, 6, 8, 9, 11, 13, 15 What are the five numbers?

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

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Can you arrange the digits 1, 1, 2, 2, 3 and 3 to make a Number Sandwich?