![In Between](/sites/default/files/styles/medium/public/thumbnails/content-01-12-15plus3-icon.jpg?itok=flrJsJPK)
Inequalities
![In Between](/sites/default/files/styles/medium/public/thumbnails/content-01-12-15plus3-icon.jpg?itok=flrJsJPK)
![Biggest enclosure](/sites/default/files/styles/medium/public/thumbnails/content-98-08-15plus2-icon.jpg?itok=p0tFrjkU)
problem
Biggest enclosure
Three fences of different lengths form three sides of an enclosure. What arrangement maximises the area?
![Eyes Down](/sites/default/files/styles/medium/public/thumbnails/content-98-11-15plus1-icon.jpg?itok=Y1xWb-ZZ)
problem
Eyes Down
The symbol [ ] means 'the integer part of'. Can the numbers [2x];
2[x]; [x + 1/2] + [x - 1/2] ever be equal? Can they ever take three
different values?
![Approximating Pi](/sites/default/files/styles/medium/public/thumbnails/content-02-05-six2-icon.jpg?itok=r817IXMl)
problem
Approximating Pi
By inscribing a circle in a square and then a square in a circle
find an approximation to pi. By using a hexagon, can you improve on
the approximation?
![Mediant madness](/sites/default/files/styles/medium/public/thumbnails/content-02-03-six4-icon.jpg?itok=E8JXQyJn)
![Plutarch's Boxes](/sites/default/files/styles/medium/public/thumbnails/content-00-12-six6-icon.jpg?itok=6J6RpXwp)
problem
Plutarch's Boxes
According to Plutarch, the Greeks found all the rectangles with
integer sides, whose areas are equal to their perimeters. Can you
find them? What rectangular boxes, with integer sides, have their
surface areas equal to their volumes?
![Comparing Continued Fractions](/sites/default/files/styles/medium/public/thumbnails/content-00-10-six5-icon.gif?itok=1SsZMoRV)
![Unit Interval](/sites/default/files/styles/medium/public/thumbnails/content-99-09-six4-icon.jpg?itok=cSzUehSi)
problem
Unit Interval
Take any two numbers between 0 and 1. Prove that the sum of the
numbers is always less than one plus their product?
![Giants](/sites/default/files/styles/medium/public/thumbnails/content-99-06-six2-icon.png?itok=eXJ-Jnul)
![Inequalities](/sites/default/files/styles/medium/public/thumbnails/content-99-02-six3-icon.jpg?itok=BjhCKmq0)
problem
Inequalities
A bag contains 12 marbles. There are more red than green but green
and blue together exceed the reds. The total of yellow and green
marbles is more than the total of red and blue. How many of each
colour there are in the bag?