I recently bought a game system Nintendo DS Lite. I also bought Super Mario DS game, but I do not understand why he is skipping levels 4 and 7 I have collected all the coins in the previous levels, and know what I need to get a level 4 and 7 Can anyone help me here?


You’re skipping Worlds 4 and 7 because they’re secret Worlds. To get access to them:
How to get World 4: Beat the World 4 boss with Mini Mario. Good luck on that. (recommend wall jumping when the boss will appear at the other side of the room)
How to get World 7: Beat the World 7 boss with Mini Mario. Slightly easier.
You have to beat levels 3 castle and 6 castle as mini Mario! The best way to do it is get to the enemy while u r big and eat the blue mushroom!