This Sudoku, based on differences. Using the one clue number can you find the solution?
Can you order pictures of the development of a frog from frogspawn
and of a bean seed growing into a plant?
Place the numbers 1 to 8 in the circles so that no consecutive
numbers are joined by a line.
You have been given nine weights, one of which is slightly heavier
than the rest. Can you work out which weight is heavier in just two
weighings of the balance?
Use the clues to work out which cities Mohamed, Sheng, Tanya and
Bharat live in.
Solve this Sudoku puzzle whose clues are in the form of sums of the
numbers which should appear in diagonal opposite cells.
This challenge extends the Plants investigation so now four or more children are involved.
A particular technique for solving Sudoku puzzles, known as "naked pair", is explained in this easy-to-read article.
A magician took a suit of thirteen cards and held them in his hand
face down. Every card he revealed had the same value as the one he
had just finished spelling. How did this work?
Four friends must cross a bridge. How can they all cross it in just
A man has 5 coins in his pocket. Given the clues, can you work out
what the coins are?
If these elves wear a different outfit every day for as many days
as possible, how many days can their fun last?
Try out the lottery that is played in a far-away land. What is the
chance of winning?
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.
Bellringers have a special way to write down the patterns they
ring. Learn about these patterns and draw some of your own.
Seven friends went to a fun fair with lots of scary rides. They
decided to pair up for rides until each friend had ridden once with
each of the others. What was the total number rides?
Exactly 195 digits have been used to number the pages in a book.
How many pages does the book have?
Make a pair of cubes that can be moved to show all the days of the
month from the 1st to the 31st.
A package contains a set of resources designed to develop
students’ mathematical thinking. This package places a
particular emphasis on “being systematic” and is
designed to meet. . . .
An extra constraint means this Sudoku requires you to think in
diagonals as well as horizontal and vertical lines and boxes of
Can you arrange the numbers 1 to 17 in a row so that each adjacent
pair adds up to a square number?
In a square in which the houses are evenly spaced, numbers 3 and 10
are opposite each other. What is the smallest and what is the
largest possible number of houses in the square?
Can you find which shapes you need to put into the grid to make the
totals at the end of each row and the bottom of each column?
What happens when you add three numbers together? Will your answer be odd or even? How do you know?
Use the differences to find the solution to this Sudoku.
A few extra challenges set by some young NRICH members.
Four small numbers give the clue to the contents of the four
Move your counters through this snake of cards and see how far you
can go. Are you surprised by where you end up?
Can you use the information to find out which cards I have used?
When you throw two regular, six-faced dice you have more chance of getting one particular result than any other. What result would that be? Why is this?
My local DIY shop calculates the price of its windows according to the area of glass and the length of frame used. Can you work out how they arrived at these prices?
Sweets are given out to party-goers in a particular way. Investigate the total number of sweets received by people sitting in different positions.
I was in my car when I noticed a line of four cars on the lane next
to me with number plates starting and ending with J, K, L and M.
What order were they in?
Roll two red dice and a green dice. Add the two numbers on the red dice and take away the number on the green. What are all the different possibilities that could come up?
Rather than using the numbers 1-9, this sudoku uses the nine
different letters used to make the words "Advent Calendar".
Can you use your powers of logic and deduction to work out the missing information in these sporty situations?
Follow the clues to find the mystery number.
Tim had nine cards each with a different number from 1 to 9 on it.
How could he have put them into three piles so that the total in
each pile was 15?
Find out about Magic Squares in this article written for students. Why are they magic?!
This practical challenge invites you to investigate the different
squares you can make on a square geoboard or pegboard.
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. . . .
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....?
Are all the possible combinations of two shapes included in this
set of 27 cards? How do you know?
There are seven pots of plants in a greenhouse. They have lost
their labels. Perhaps you can help re-label them.
Different combinations of the weights available allow you to make different totals. Which totals can you make?
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?
A Sudoku with a twist.
A Sudoku with clues as ratios.
The ancient Egyptians were said to make right-angled triangles
using a rope with twelve equal sections divided by knots. What
other triangles could you make if you had a rope like this?
Alice's mum needs to go to each child's house just once and then
back home again. How many different routes are there? Use the
information to find out how long each road is on the route she