I start with a red, a blue, a green and a yellow marble. I can
trade any of my marbles for three others, one of each colour. Can I
end up with exactly two marbles of each colour?
The triangle ABC is equilateral. The arc AB has centre C, the arc
BC has centre A and the arc CA has centre B. Explain how and why
this shape can roll along between two parallel tracks.
Can you use small coloured cubes to make a 3 by 3 by 3 cube so that each face of the bigger cube contains one of each colour?
I start with 3 marbles, one red, one green and one blue.
I can trade any one marble for two others, one each of the other two colours.
Is it possible to make a number of such trades and end up with five more blue marbles than red?
I don't care how many green marbles I have at the end.