![Xavi's T-shirt](/sites/default/files/styles/medium/public/thumbnails/content-id-15208-icon.png?itok=p09ReWyq)
![Parallel lines](/sites/default/files/styles/medium/public/thumbnails/content-id-5609-icon.jpg?itok=WNXYu0AW)
problem
Parallel lines
How does the position of the line affect the equation of the line?
What can you say about the equations of parallel lines?
![In the bag](/sites/default/files/styles/medium/public/thumbnails/content-id-6016-icon.jpg?itok=kXQEDWEf)
problem
In the bag
Can you guess the colours of the 10 marbles in the bag? Can you develop an effective strategy for reaching 1000 points in the least number of rounds?
![Elevenses](/sites/default/files/styles/medium/public/thumbnails/content-id-6390-icon.png?itok=1dcdS-Fl)
problem
Elevenses
How many pairs of numbers can you find that add up to a multiple of 11? Do you notice anything interesting about your results?
![Reflecting Lines](/sites/default/files/styles/medium/public/thumbnails/content-id-6471-icon.jpg?itok=_vqW58fF)
problem
Reflecting Lines
Investigate what happens to the equations of different lines when you reflect them in one of the axes. Try to predict what will happen. Explain your findings.
![Translating Lines](/sites/default/files/styles/medium/public/thumbnails/translating-lines.jpg?itok=_v1DZ7lJ)
problem
Translating Lines
Investigate what happens to the equation of different lines when
you translate them. Try to predict what will happen. Explain your
findings.
![Cyclic Quadrilaterals](/sites/default/files/styles/medium/public/thumbnails/content-id-6624-icon.jpg?itok=tQcnV8ND)
problem
Cyclic Quadrilaterals
Draw some quadrilaterals on a 9-point circle and work out the angles. Is there a theorem?
![Growing Surprises](/sites/default/files/styles/medium/public/thumbnails/content-id-11212-icon.jpg?itok=bs0Du2U4)
![Days and Dates](/sites/default/files/styles/medium/public/thumbnails/content-00-04-15plus1-icon.png?itok=iJ_VkR9D)
problem
Days and Dates
Investigate how you can work out what day of the week your birthday will be on next year, and the year after...
![What's it worth?](/sites/default/files/styles/medium/public/thumbnails/content-01-04-penta5-icon.gif?itok=gGcp640G)
problem
What's it worth?
There are lots of different methods to find out what the shapes are worth - how many can you find?
![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.
![Special Numbers](/sites/default/files/styles/medium/public/thumbnails/content-02-08-penta3-icon.png?itok=Z7DZGoxN)
problem
Special Numbers
My two digit number is special because adding the sum of its digits to the product of its digits gives me my original number. What could my number be?
![Tilted Squares](/sites/default/files/styles/medium/public/thumbnails/content-id-2293-icon.png?itok=q-hpU9S_)
problem
Tilted Squares
It's easy to work out the areas of most squares that we meet, but what if they were tilted?
![Mixing Paints](/sites/default/files/styles/medium/public/thumbnails/content-id-4793-icon.png?itok=S18g7PDu)
![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.
![Terminating or not](/sites/default/files/styles/medium/public/thumbnails/content-id-14531-icon.jpg?itok=eRQghi_3)
problem
Terminating or not
Is there a quick way to work out whether a fraction terminates or recurs when you write it as a decimal?
![Marbles in a box](/sites/default/files/styles/medium/public/thumbnails/content-03-02-six2-icon.gif?itok=8LI6k1CK)
problem
Marbles in a box
How many winning lines can you make in a three-dimensional version of noughts and crosses?
![Think of Two Numbers](/sites/default/files/styles/medium/public/thumbnails/content-03-05-penta2-icon.gif?itok=XIhHPBGZ)
problem
Think of Two Numbers
Think of two whole numbers under 10, and follow the steps. I can work out both your numbers very quickly. How?
![Sending a Parcel](/sites/default/files/styles/medium/public/thumbnails/content-id-2650-icon.png?itok=5AhG8l4G)
problem
Sending a Parcel
What is the greatest volume you can get for a rectangular (cuboid)
parcel if the maximum combined length and girth are 2 metres?
![How Many Miles To Go?](/sites/default/files/styles/medium/public/thumbnails/how-many-miles-to-go-.gif?itok=s4ss-dDK)
problem
How Many Miles To Go?
How many more miles must the car travel before the numbers on the milometer and the trip meter contain the same digits in the same order?
![Generating Triples](/sites/default/files/styles/medium/public/thumbnails/content-id-7282-icon.png?itok=rxebyRVc)
problem
Generating Triples
Sets of integers like 3, 4, 5 are called Pythagorean Triples, because they could be the lengths of the sides of a right-angled triangle. Can you find any more?
![Tree tops](/sites/default/files/styles/medium/public/thumbnails/content-03-06-six1-icon.jpg?itok=lB4lluZf)
problem
Tree tops
Can you make sense of information about trees in order to maximise the profits of a forestry company?