Investigate the different shaped bracelets you could make from 18 different spherical beads. How do they compare if you use 24 beads?
What is the greatest number of counters you can place on the grid below without four of them lying at the corners of a square?
The idea of this game is to add or subtract the two numbers on the dice and cover the result on the grid, trying to get a line of three. Are there some numbers that are good to aim for?