![One Big Triangle](/sites/default/files/styles/medium/public/thumbnails/content-01-04-letme1-icon.png?itok=AsMMvuUN)
problem
One Big Triangle
Make one big triangle so the numbers that touch on the small triangles add to 10.
![Butterfly Flowers](/sites/default/files/styles/medium/public/thumbnails/content-02-09-letme1-icon.gif?itok=zCExKNNO)
problem
Butterfly Flowers
Can you find two butterflies to go on each flower so that the numbers on each pair of butterflies adds to the number on their flower?
![Same Length Trains](/sites/default/files/styles/medium/public/thumbnails/content-id-4332-icon.png?itok=rMNg0K3s)
problem
Same Length Trains
How many trains can you make which are the same length as Matt's and Katie's, using rods that are identical?
![What's in a Name?](/sites/default/files/styles/medium/public/thumbnails/content-99-11-penta1-icon.gif?itok=81VflGfg)
problem
What's in a Name?
What do you notice about these squares of numbers? What is the same? What is different?
![I'm Eight](/sites/default/files/styles/medium/public/thumbnails/content-98-11-bbprob2-icon.png?itok=y1X7RsxW)
![Number match](/sites/default/files/styles/medium/public/thumbnails/content-id-6937-icon.png?itok=yALZ7u94)
problem
Number match
A task which depends on members of the group noticing the needs of others and responding.
![I Like ...](/sites/default/files/styles/medium/public/thumbnails/content-id-6962-icon.gif?itok=iN64Angn)
problem
I Like ...
Mr Gilderdale is playing a game with his class. What rule might he have chosen? How would you test your idea?
![Even and odd](/sites/default/files/styles/medium/public/thumbnails/content-id-6895-icon.png?itok=koeHIdLD)
problem
Even and odd
This activity is best done with a whole class or in a large group. Can you match the cards? What happens when you add pairs of the numbers together?
![All Change](/sites/default/files/styles/medium/public/thumbnails/content-id-7514-icon.png?itok=6OwAYqbZ)
problem
All Change
There are three versions of this challenge. The idea is to change the colour of all the spots on the grid. Can you do it in fewer throws of the dice?
![Cuisenaire Counting](/sites/default/files/styles/medium/public/thumbnails/content-id-2724-icon.png?itok=Wuz6psIg)
problem
Cuisenaire Counting
Here are some rods that are different colours. How could I make a yellow rod using white and red rods?
![Domino Sorting](/sites/default/files/styles/medium/public/thumbnails/content-id-4940-icon.png?itok=SPWEiiSU)
problem
Domino Sorting
Try grouping the dominoes in the ways described. Are there any left over each time? Can you explain why?
![That number square](/sites/default/files/styles/medium/public/thumbnails/content-id-8169-icon.jpg?itok=RXd521Qj)
problem
That number square
Exploring the structure of a number square: how quickly can you put the number tiles in the right place on the grid?
![Ip Dip](/sites/default/files/styles/medium/public/thumbnails/content-id-7185-icon.gif?itok=t93ltWdE)
problem
Ip Dip
"Ip dip sky blue! Who's 'it'? It's you!" Where would you position yourself so that you are 'it' if there are two players? Three players ...?
![Strike it Out](/sites/default/files/styles/medium/public/thumbnails/content-id-6589-icon.gif?itok=PtQ_v8tW)
problem
Strike it Out
Use your addition and subtraction skills, combined with some strategic thinking, to beat your partner at this game.
![Sort them out (1)](/sites/default/files/styles/medium/public/thumbnails/content-id-6885-icon.png?itok=H3gzuY3t)
problem
Sort them out (1)
Can you each work out the number on your card? What do you notice? How could you sort the cards?
![Eightness of Eight](/sites/default/files/styles/medium/public/thumbnails/content-id-13704-icon.png?itok=M0Vg23eS)
problem
Eightness of Eight
What do you see as you watch this video? Can you create a similar video for the number 12?
![The add and take-away path](/sites/default/files/styles/medium/public/thumbnails/content-id-7281-icon.jpg?itok=BFClBmAp)
problem
The add and take-away path
Two children made up a game as they walked along the garden paths. Can you find out their scores? Can you find some paths of your own?
![Ordering cards](/sites/default/files/styles/medium/public/thumbnails/content-id-8058-icon.png?itok=dNwJ9YCR)
problem
Ordering cards
This problem is designed to help children to learn, and to use, the two and three times tables.
![Digit Addition](/sites/default/files/styles/medium/public/thumbnails/content-id-14312-icon.png?itok=5rMz7AQJ)
problem
Digit Addition
Try out this number trick. What happens with different starting numbers? What do you notice?
![Half Time](/sites/default/files/styles/medium/public/thumbnails/content-id-7408-icon.jpg?itok=JF-ETQem)
![How Many?](/sites/default/files/styles/medium/public/thumbnails/content-id-14404-icon.jpg?itok=z7bV1aR8)
problem
How Many?
Have a look at these photos of different fruit. How many do you see? How did you count?
![Double or Halve?](/sites/default/files/styles/medium/public/thumbnails/content-id-10654-icon.png?itok=Uz7E73ZF)
problem
Double or Halve?
Throw the dice and decide whether to double or halve the number. Will you be the first to reach the target?
![Are you well Balanced?](/sites/default/files/styles/medium/public/thumbnails/content-id-4734-icon.png?itok=LtGVHatm)
problem
Are you well Balanced?
Can you work out how to make each side of this balance equally balanced? You can put more than one weight on a hook.
![Always, Sometimes or Never?](/sites/default/files/styles/medium/public/thumbnails/content-id-12670-icon.png?itok=UGVEdfeW)
problem
Always, Sometimes or Never?
Are these statements relating to odd and even numbers always true, sometimes true or never true?
![How do you see it?](/sites/default/files/styles/medium/public/thumbnails/content-id-8296-icon.png?itok=wP5NYAaI)
problem
How do you see it?
Here are some short problems for you to try. Talk to your friends about how you work them out.
![Birthday Sharing](/sites/default/files/styles/medium/public/thumbnails/content-id-14052-icon.png?itok=uHtu7Neb)
problem
Birthday Sharing
It's Sahila's birthday and she is having a party. How could you answer these questions using a picture, with things, with numbers or symbols?
![Growing Garlic](/sites/default/files/styles/medium/public/thumbnails/content-id-5579-icon.png?itok=3gT7Jloo)
problem
Growing Garlic
Ben and his mum are planting garlic. Can you find out how many cloves of garlic they might have had?
![Tables Teaser](/sites/default/files/styles/medium/public/thumbnails/content-id-14242-icon.png?itok=4Li13yQB)
problem
Tables Teaser
How will you work out which numbers have been used to create this multiplication square?
![Dicey Addition](/sites/default/files/styles/medium/public/thumbnails/content-id-11863-icon.png?itok=JxXPSevO)
![Arranging Additions and Sorting Subtractions](/sites/default/files/styles/medium/public/thumbnails/content-id-14726-icon.png?itok=JpyCE6wp)
problem
Arranging Additions and Sorting Subtractions
Order these four calculations from easiest to hardest. How did you decide?
![Subtraction Slip](/sites/default/files/styles/medium/public/thumbnails/content-id-14740-icon.jpg?itok=M2VCKxJ5)
problem
Subtraction Slip
Can you spot the mistake in this video? How would you work out the answer to this calculation?
![Biscuit Decorations](/sites/default/files/styles/medium/public/thumbnails/content-99-07-letme1-icon.jpg?itok=wI9HyT8O)
problem
Biscuit Decorations
Andrew decorated 20 biscuits to take to a party. He lined them up and put icing on every second biscuit and different decorations on other biscuits. How many biscuits weren't decorated?
![Equivalent Pairs](/sites/default/files/styles/medium/public/thumbnails/content-id-14816-icon.jpg?itok=QnD2a1tJ)
![Next Domino](/sites/default/files/styles/medium/public/thumbnails/content-00-03-letme1-icon.png?itok=gx2ASzuK)
![Placeholder: several colourful numbers](/themes/nrich/images/nrich_small_placeholder.png)
project
How Many?
This project challenges you to work out the number of cubes hidden under a cloth. What questions would you like to ask?
![Domino Sequences](/sites/default/files/styles/medium/public/thumbnails/content-03-03-letme1-icon.gif?itok=6U1wpha0)
![Fraction Match](/sites/default/files/styles/medium/public/thumbnails/content-id-6938-icon.png?itok=Je0O9lK1)
problem
Fraction Match
A task which depends on members of the group noticing the needs of others and responding.
![Robot Monsters](/sites/default/files/styles/medium/public/thumbnails/content-id-2404-icon.png?itok=IwqQPq78)
problem
Robot Monsters
Use these head, body and leg pieces to make Robot Monsters which are different heights.
![Birthday Cakes](/sites/default/files/styles/medium/public/thumbnails/content-03-05-letme2-icon.gif?itok=9UlNs-ri)
problem
Birthday Cakes
Jack's mum bought some candles to use on his birthday cakes and when his sister was born, she used them on her cakes too. Can you use the information to find out when Kate was born?
![Secret Number](/sites/default/files/styles/medium/public/thumbnails/content-id-5651-icon.png?itok=JIKXpI6V)
problem
Secret Number
Annie and Ben are playing a game with a calculator. What was Annie's secret number?
![Jumping squares](/sites/default/files/styles/medium/public/thumbnails/content-id-7471-icon.png?itok=zhe2tIx9)
problem
Jumping squares
In this problem it is not the squares that jump, you do the jumping! The idea is to go round the track in as few jumps as possible.
![Ring a Ring of Numbers](/sites/default/files/styles/medium/public/thumbnails/content-id-2782-icon.png?itok=90NvaFQb)
problem
Ring a Ring of Numbers
Choose four of the numbers from 1 to 9 to put in the squares so that the differences between joined squares are odd.
![6 Beads](/sites/default/files/styles/medium/public/thumbnails/content-99-06-letme1-icon.png?itok=YH8jRl8P)
problem
6 Beads
If you put three beads onto a tens/ones abacus you can make the numbers 3, 30, 12 or 21. What numbers can be made with six beads?
![Making Sticks](/sites/default/files/styles/medium/public/thumbnails/content-02-10-letme1-icon.gif?itok=Qza9c5tO)
problem
Making Sticks
Kimie and Sebastian were making sticks from interlocking cubes and lining them up. Can they make their lines the same length? Can they make any other lines?
![The Tall Tower](/sites/default/files/styles/medium/public/thumbnails/content-id-2354-icon.png?itok=eeytH4_a)
problem
The Tall Tower
As you come down the ladders of the Tall Tower you collect useful spells. Which way should you go to collect the most spells?
![Grouping Goodies](/sites/default/files/styles/medium/public/thumbnails/content-02-10-letme2-icon.gif?itok=BcSOezhs)
problem
Grouping Goodies
Pat counts her sweets in different groups and both times she has some left over. How many sweets could she have had?
![4 Dom](/sites/default/files/styles/medium/public/thumbnails/content-00-09-letme2-icon.png?itok=CUtems6A)
problem
4 Dom
Use these four dominoes to make a square that has the same number of dots on each side.
![Bryony's Triangle](/sites/default/files/styles/medium/public/thumbnails/content-id-7392-icon.jpg?itok=L3-YhaCi)
problem
Bryony's Triangle
Watch the video to see how to fold a square of paper to create a flower. What fraction of the piece of paper is the small triangle?
![Number Differences](/sites/default/files/styles/medium/public/thumbnails/content-id-2790-icon.jpg?itok=19is85tw)
problem
Number Differences
Place the numbers from 1 to 9 in the squares below so that the difference between joined squares is odd. How many different ways can you do this?
![Matching fractions](/sites/default/files/styles/medium/public/thumbnails/content-id-8283-icon.gif?itok=NNFU_a6q)
problem
Matching fractions
Can you find different ways of showing the same fraction? Try this matching game and see.
![Tumbling Down](/sites/default/files/styles/medium/public/thumbnails/content-id-13728-icon.png?itok=ovhAwmmm)
![First Connect Three](/sites/default/files/styles/medium/public/thumbnails/content-id-5865-icon.png?itok=04WHK5zo)
problem
First Connect Three
Add or subtract the two numbers on the spinners and try to complete a row of three. Are there some numbers that are good to aim for?
![Magic Vs](/sites/default/files/styles/medium/public/thumbnails/content-id-6274-icon.png?itok=dRZNbkAI)
problem
Magic Vs
Can you put the numbers 1-5 in the V shape so that both 'arms' have the same total?
![Sweets in a box](/sites/default/files/styles/medium/public/thumbnails/content-00-12-bbprob1-icon.jpg?itok=WT5n0fd-)
problem
Sweets in a box
How many different shaped boxes can you design for 36 sweets in one layer? Can you arrange the sweets so that no sweets of the same colour are next to each other in any direction?
![Coded hundred square](/sites/default/files/styles/medium/public/thumbnails/content-id-6554-icon.png?itok=NQUPJ0QK)
problem
Coded hundred square
This 100 square jigsaw is written in code. It starts with 1 and ends with 100. Can you build it up?
![Highest and Lowest](/sites/default/files/styles/medium/public/thumbnails/content-99-04-penta5-icon.jpg?itok=Ikk6pjwc)
problem
Highest and Lowest
Put operations signs between the numbers 3 4 5 6 to make the highest possible number and lowest possible number.
![The Moons of Vuvv](/sites/default/files/styles/medium/public/thumbnails/content-01-07-penta3-icon.gif?itok=xHgSC_ox)
problem
The Moons of Vuvv
The planet of Vuvv has seven moons. Can you work out how long it is between each super-eclipse?
![Times Tables Shifts](/sites/default/files/styles/medium/public/thumbnails/content-id-6863-icon.jpg?itok=2WjKpBW7)
problem
Times Tables Shifts
In this activity, the computer chooses a times table and shifts it. Can you work out the table and the shift each time?
![Planning a School Trip](/sites/default/files/styles/medium/public/thumbnails/content-id-6969-icon.png?itok=EHfUZY3X)
problem
Planning a School Trip
You are organising a school trip and you need to write a letter to parents to let them know about the day. Use the cards to gather all the information you need.
![Multiplication Squares](/sites/default/files/styles/medium/public/thumbnails/content-02-10-penta1-icon.gif?itok=xvTs90p3)
problem
Multiplication Squares
Can you work out the arrangement of the digits in the square so that the given products are correct? The numbers 1 - 9 may be used once and once only.
![How do you do it?](/sites/default/files/styles/medium/public/thumbnails/content-id-6901-icon.gif?itok=DU3xchZB)
problem
How do you do it?
This group activity will encourage you to share calculation strategies and to think about which strategy might be the most efficient.
![Take three numbers](/sites/default/files/styles/medium/public/thumbnails/content-id-8063-icon.png?itok=xAzr90zq)
problem
Take three numbers
What happens when you add three numbers together? Will your answer be odd or even? How do you know?
![Representing Numbers](/sites/default/files/styles/medium/public/thumbnails/content-id-13272-icon.jpg?itok=j-U6Pg6J)
problem
Representing Numbers
Find as many different ways of representing this number of dots as you can.
![Trebling](/sites/default/files/styles/medium/public/thumbnails/content-03-11-penta1-icon.gif?itok=Gu7SmX2J)
![Journeys in Numberland](/sites/default/files/styles/medium/public/thumbnails/content-id-7285-icon.jpg?itok=G_TGMSH-)
problem
Journeys in Numberland
Tom and Ben visited Numberland. Use the maps to work out the number of points each of their routes scores.
![Carrying Cards](/sites/default/files/styles/medium/public/thumbnails/content-id-2726-icon.png?itok=BG7Qhv6t)
problem
Carrying Cards
These sixteen children are standing in four lines of four, one behind the other. They are each holding a card with a number on it. Can you work out the missing numbers?
![An Easy Way to Multiply by 10?](/sites/default/files/styles/medium/public/thumbnails/content-id-2772-icon.jpg?itok=jiT2oq21)
problem
An Easy Way to Multiply by 10?
Do you agree with Badger's statements? Is Badger's reasoning 'watertight'? Why or why not?
![Let us divide!](/sites/default/files/styles/medium/public/thumbnails/content-id-8308-icon.png?itok=aX9M_8zD)
problem
Let us divide!
Look at different ways of dividing things. What do they mean? How might you show them in a picture, with things, with numbers and symbols?
![Less is More](/sites/default/files/styles/medium/public/thumbnails/content-id-14684-icon.png?itok=J-d_NO-x)
problem
Less is More
Use your knowledge of place value to try to win this game. How will you maximise your score?
![Fifteen cards](/sites/default/files/styles/medium/public/thumbnails/content-id-7506-icon.png?itok=z3XnnkJh)
![Always, Sometimes or Never? Number](/sites/default/files/styles/medium/public/thumbnails/content-id-12672-icon.png?itok=UuM6k13s)
problem
Always, Sometimes or Never? Number
Are these statements always true, sometimes true or never true?
![Shape Times Shape](/sites/default/files/styles/medium/public/thumbnails/content-id-5714-icon.png?itok=Pu4-NNY7)
problem
Shape Times Shape
These eleven shapes each stand for a different number. Can you use the number sentences to work out what they are?
![Picture Your Method](/sites/default/files/styles/medium/public/thumbnails/content-id-14736-icon.jpg?itok=S45wDqrO)
problem
Picture Your Method
Can you match these calculation methods to their visual representations?
![Which symbol?](/sites/default/files/styles/medium/public/thumbnails/content-id-6777-icon.png?itok=RZG-oytk)
![Compare the Calculations](/sites/default/files/styles/medium/public/thumbnails/content-id-14739-icon.png?itok=YPXkXLlg)
problem
Compare the Calculations
Can you put these four calculations into order of difficulty? How did you decide?
![Space distances](/sites/default/files/styles/medium/public/thumbnails/content-id-13270-icon.jpg?itok=Zx53BivC)
problem
Space distances
This task focuses on distances travelled by the asteroid Florence. It's an opportunity to work with very large numbers.
![Fractional Triangles](/sites/default/files/styles/medium/public/thumbnails/content-02-04-penta3-icon.jpg?itok=6i8hOuSG)
problem
Fractional Triangles
Use the lines on this figure to show how the square can be divided into 2 halves, 3 thirds, 6 sixths and 9 ninths.
![The Deca Tree](/sites/default/files/styles/medium/public/thumbnails/content-03-11-penta3-icon.gif?itok=D7FT8z2q)
problem
The Deca Tree
Find out what a Deca Tree is and then work out how many leaves there will be after the woodcutter has cut off a trunk, a branch, a twig and a leaf.
![Twenty Divided into Six](/sites/default/files/styles/medium/public/thumbnails/content-01-03-penta4-icon.gif?itok=deaYoy4U)
problem
Twenty Divided into Six
Katie had a pack of 20 cards numbered from 1 to 20. She arranged the cards into 6 unequal piles where each pile added to the same total. What was the total and how could this be done?
![Reach 100](/sites/default/files/styles/medium/public/thumbnails/content-02-09-penta2-icon.gif?itok=VCjD2daE)
problem
Reach 100
Choose four different digits from 1-9 and put one in each box so that the resulting four two-digit numbers add to a total of 100.
![Sealed Solution](/sites/default/files/styles/medium/public/thumbnails/content-03-06-penta4-icon.gif?itok=doeBT_KV)
problem
Sealed Solution
Ten cards are put into five envelopes so that there are two cards in each envelope. The sum of the numbers inside it is written on each envelope. What numbers could be inside the envelopes?
![Got It](/sites/default/files/styles/medium/public/thumbnails/content-02-01-game1-icon.png?itok=YpX97D5X)
problem
Got It
A game for two people, or play online. Given a target number, say 23, and a range of numbers to choose from, say 1-4, players take it in turns to add to the running total to hit their target.
![Mystery Matrix](/sites/default/files/styles/medium/public/thumbnails/content-01-09-penta2-icon.png?itok=QvnkPfB_)
problem
Mystery Matrix
Can you fill in this table square? The numbers 2 -12 were used to generate it with just one number used twice.
![All the Digits](/sites/default/files/styles/medium/public/thumbnails/content-02-09-penta1-icon.png?itok=nuAeRKtn)
problem
All the Digits
This multiplication uses each of the digits 0 - 9 once and once only. Using the information given, can you replace the stars in the calculation with figures?
![Factor Lines](/sites/default/files/styles/medium/public/thumbnails/content-02-10-penta5-icon.gif?itok=RIygcdS8)
problem
Factor Lines
Arrange the four number cards on the grid, according to the rules, to make a diagonal, vertical or horizontal line.
![Table patterns go wild!](/sites/default/files/styles/medium/public/thumbnails/content-id-6924-icon.png?itok=_L0q3bAS)
problem
Table patterns go wild!
Nearly all of us have made table patterns on hundred squares, that is 10 by 10 grids. This problem looks at the patterns on differently sized square grids.
![Three neighbours](/sites/default/files/styles/medium/public/thumbnails/content-id-8108-icon.gif?itok=eZEBmBsF)
![Counting Cogs](/sites/default/files/styles/medium/public/thumbnails/content-id-6966-icon.gif?itok=-yx-oxgg)
problem
Counting Cogs
Which pairs of cogs let the coloured tooth touch every tooth on the other cog? Which pairs do not let this happen? Why?
![Two Primes Make One Square](/sites/default/files/styles/medium/public/thumbnails/content-03-01-penta2-icon.gif?itok=UNPMgYqh)
problem
Two Primes Make One Square
Can you make square numbers by adding two prime numbers together?
![Remainders](/sites/default/files/styles/medium/public/thumbnails/content-96-11-six4-icon.png?itok=5cZcyZQE)
problem
Remainders
I'm thinking of a number. My number is both a multiple of 5 and a multiple of 6. What could my number be?
![Number Lines in Disguise](/sites/default/files/styles/medium/public/thumbnails/content-id-13452-icon.jpg?itok=w1sVtOJy)
problem
Number Lines in Disguise
Some of the numbers have fallen off Becky's number line. Can you figure out what they were?
![Multiples Grid](/sites/default/files/styles/medium/public/thumbnails/content-id-5429-icon.png?itok=S2WRt3VQ)
problem
Multiples Grid
What do the numbers shaded in blue on this hundred square have in common? What do you notice about the pink numbers? How about the shaded numbers in the other squares?
![Factor-Multiple Chains](/sites/default/files/styles/medium/public/thumbnails/content-id-5578-icon.png?itok=_LqJl9mK)
problem
Factor-Multiple Chains
Can you see how these factor-multiple chains work? Find the chain which contains the smallest possible numbers. How about the largest possible numbers?
![Six Numbered Cubes](/sites/default/files/styles/medium/public/thumbnails/content-id-10918-icon.png?itok=R9ReuN0z)
![What Distance?](/sites/default/files/styles/medium/public/thumbnails/content-id-13267-icon.png?itok=ut5KGqxQ)
problem
What Distance?
Can you use addition and subtraction to answer these questions about real-life distances?
![Forgot the Numbers](/sites/default/files/styles/medium/public/thumbnails/content-00-09-penta2-icon.gif?itok=80HGuyzk)
problem
Forgot the Numbers
On my calculator I divided one whole number by another whole number and got the answer 3.125. If the numbers are both under 50, what are they?
![Doughnut percents](/sites/default/files/styles/medium/public/thumbnails/content-id-6945-icon.jpg?itok=KYyqyhQF)
problem
Doughnut percents
A task involving the equivalence between fractions, percentages and decimals which depends on members of the group noticing the needs of others and responding.
![Chocolate](/sites/default/files/styles/medium/public/thumbnails/content-98-01-bbprob1-icon.gif?itok=ZVBQ8Cwf)
problem
Chocolate
There are three tables in a room with blocks of chocolate on each. Where would be the best place for each child in the class to sit if they came in one at a time?
![Roll these Dice](/sites/default/files/styles/medium/public/thumbnails/content-98-10-bbprob2-icon.png?itok=cj85bw5d)
problem
Roll these Dice
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 possible answers?
![Pumpkin Pie Problem](/sites/default/files/styles/medium/public/thumbnails/content-00-11-penta3-icon.png?itok=FdWXK1jP)
problem
Pumpkin Pie Problem
Peter wanted to make two pies for a party. His mother had a recipe for him to use. However, she always made 80 pies at a time. Did Peter have enough ingredients to make two pumpkin pies?