![missing multipliers](/sites/default/files/styles/medium/public/thumbnails/content-id-7382-icon.jpg?itok=6uMY2Jib)
problem
Missing Multipliers
What is the smallest number of answers you need to reveal in order to work out the missing headers?
![Consecutive Numbers](/sites/default/files/styles/medium/public/thumbnails/content-97-11-bbprob2-icon.jpg?itok=C_UREbsv)
problem
Consecutive Numbers
An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.
![5 by 5 Mathdokus](/sites/default/files/styles/medium/public/thumbnails/content-id-15107-icon.png?itok=Shua5c9Y)
![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?
![Method in multiplying madness?](/sites/default/files/styles/medium/public/thumbnails/content-id-5612-icon.png?itok=ZHpntMLH)
problem
Method in multiplying madness?
Watch our videos of multiplication methods that you may not have met before. Can you make sense of them?
![Two and Two](/sites/default/files/styles/medium/public/thumbnails/content-01-06-six2-icon.png?itok=r2AsNoHS)
problem
Two and Two
How many solutions can you find to this sum? Each of the different letters stands for a different number.
![Largest product](/sites/default/files/styles/medium/public/thumbnails/content-96-11-six6-icon.png?itok=visW6w7i)
![Cinema Problem](/sites/default/files/styles/medium/public/thumbnails/content-03-10-six1-icon.gif?itok=-Hhp0rJ9)
problem
Cinema Problem
A cinema has 100 seats. Show how it is possible to sell exactly 100 tickets and take exactly £100 if the prices are £10 for adults, 50p for pensioners and 10p for children.
![Consecutive Seven](/sites/default/files/styles/medium/public/thumbnails/content-id-2661-icon.png?itok=mnxknoG7)
problem
Consecutive Seven
Can you arrange these numbers into 7 subsets, each of three numbers, so that when the numbers in each are added together, they make seven consecutive numbers?
![Fractions jigsaw](/sites/default/files/styles/medium/public/thumbnails/content-id-5467-icon.png?itok=zwPZDGJg)
![Round and round and round](/sites/default/files/styles/medium/public/thumbnails/content-id-5617-icon.png?itok=Vimw8iXp)
problem
Round and round and round
Where will the point stop after it has turned through 30 000 degrees? I took out my calculator and typed 30 000 ÷ 360. How did this help?
![Keep it simple](/sites/default/files/styles/medium/public/thumbnails/keep-it-simple.gif?itok=xXs1GgR6)
![Countdown fractions](/sites/default/files/styles/medium/public/thumbnails/content-id-6564-icon.gif?itok=gMgDY9tV)
problem
Countdown fractions
Here is a chance to play a fractions version of the classic Countdown Game.
![Going round in circles](/sites/default/files/styles/medium/public/thumbnails/content-id-6651-icon.jpg?itok=q7CGjhH3)
problem
Going round in circles
Mathematicians are always looking for efficient methods for solving problems. How efficient can you be?
![Magic Letters](/sites/default/files/styles/medium/public/thumbnails/content-id-7821-icon.png?itok=z67LWboP)
problem
Magic Letters
Charlie has made a Magic V. Can you use his example to make some more? And how about Magic Ls, Ns and Ws?
![Strange Bank Account](/sites/default/files/styles/medium/public/thumbnails/content-id-9923-icon.jpg?itok=z5kDCAKZ)
problem
Strange Bank Account
Imagine a very strange bank account where you are only allowed to do two things...
![Making a difference](/sites/default/files/styles/medium/public/thumbnails/content-id-11012-icon.jpg?itok=Vx99Haip)
![Cryptarithms](/sites/default/files/styles/medium/public/thumbnails/content-id-11107-icon.jpg?itok=PZIqV5yE)
![Can you Make 100?](/sites/default/files/styles/medium/public/thumbnails/content-id-11819-icon.jpg?itok=TRBLygmu)
problem
Can you Make 100?
How many ways can you find to put in operation signs (+, −, ×, ÷) to make 100?
![Almost One](/sites/default/files/styles/medium/public/thumbnails/content-id-13205-icon.jpg?itok=wClBY0YZ)
![Have you got it?](/sites/default/files/styles/medium/public/thumbnails/content-02-02-15plus2-icon.gif?itok=ZqujeQid)
![Number Daisy](/sites/default/files/styles/medium/public/thumbnails/content-01-07-six1-icon.jpg?itok=MsQGFTpw)
problem
Number Daisy
Can you find six numbers to go in the Daisy from which you can make all the numbers from 1 to a number bigger than 25?
![Twisting and Turning](/sites/default/files/styles/medium/public/thumbnails/content-id-5776-icon.jpg?itok=piqO4PnB)
problem
Twisting and Turning
Take a look at the video and try to find a sequence of moves that will untangle the ropes.
![More Twisting and Turning](/sites/default/files/styles/medium/public/thumbnails/content-id-5777-icon.png?itok=ZVKeM2JB)
problem
More Twisting and Turning
It would be nice to have a strategy for disentangling any tangled ropes...
![Connect Three](/sites/default/files/styles/medium/public/thumbnails/content-id-5864-icon.jpg?itok=wTq5Aiim)
problem
Connect Three
In this game the winner is the first to complete a row of three. Are some squares easier to land on than others?
![Weights](/sites/default/files/styles/medium/public/thumbnails/content-id-5958-icon.jpg?itok=vBACsi0k)
problem
Weights
Different combinations of the weights available allow you to make different totals. Which totals can you make?
![Impossibilities](/sites/default/files/styles/medium/public/thumbnails/content-id-11109-icon.png?itok=rtI1nV8G)
![Overlaps](/sites/default/files/styles/medium/public/thumbnails/content-id-11112-icon.png?itok=qda5H61D)
![Same Answer](/sites/default/files/styles/medium/public/thumbnails/content-id-11124-icon.jpg?itok=51IjjMJv)
problem
Same Answer
Aisha's division and subtraction calculations both gave the same answer! Can you find some more examples?
![Where can we visit?](/sites/default/files/styles/medium/public/thumbnails/content-00-12-six3-icon.jpg?itok=fnQnUDU6)
problem
Where can we visit?
Charlie and Abi put a counter on 42. They wondered if they could visit all the other numbers on their 1-100 board, moving the counter using just these two operations: x2 and -5. What do you think?
![Egyptian Fractions](/sites/default/files/styles/medium/public/thumbnails/content-03-05-penta5-icon.gif?itok=zV3qUZmO)
problem
Egyptian Fractions
The Egyptians expressed all fractions as the sum of different unit fractions. Here is a chance to explore how they could have written different fractions.
![Consecutive negative numbers](/sites/default/files/styles/medium/public/thumbnails/content-id-5868-icon.jpg?itok=Ym7OX3hn)
problem
Consecutive negative numbers
Do you notice anything about the solutions when you add and/or subtract consecutive negative numbers?
![the greedy algorithm](/sites/default/files/styles/medium/public/thumbnails/content-id-6541-icon.gif?itok=Ft7nd07D)
problem
the greedy algorithm
The Egyptians expressed all fractions as the sum of different unit
fractions. The Greedy Algorithm might provide us with an efficient
way of doing this.
![The Root of the Problem](/sites/default/files/styles/medium/public/thumbnails/content-03-03-six2-icon.jpg?itok=sC256H-P)
Image
![Number operations STEM footer Number operations STEM footer](/sites/default/files/styles/large/public/thumbnails/content-id-13467-STEMlogo.png?itok=Sz2rFokR)
You may also be interested in this collection of activities from the STEM Learning website, that complement the NRICH activities above.