Can you hang weights in the right place to make the the number balance balanced?
If there are 3 squares in the ring, can you place three different numbers in them so that their differences are odd? Try with different numbers of squares around the ring. What do you notice?
Arrange the four number cards on the grid, according to the rules, to make a diagonal, vertical or horizontal line.
Sort the houses in my street into different groups. Can you do it in any other ways?
Nine squares are fitted together to form a rectangle. Can you find its dimensions?
