Move 1 coin to form 2 lines of 4 coins.
In this picture you can see 6 coins in the shape of a cross. Moving just ONE coin, can you form 2 lines, each with 4 coins?
Move 2 coins so every coin touches exactly 3 coins.
Here is a hexagon using 6 matchsticks. Move 4 matchsticks to create 2 triangles.