Just go to this site : http://www.cheatcc.com/xbox360/legoindianajonestheoriginaladventurescheatscodes.html
It has a list of cheat codes to unlock new things.
Check the related link below
You could try Lego games
Leia is a Star Wars character and wouldn't appear in the Indiana Jones set. She does appear in some Star Wars sets, however.
The math class in LEGO Indiana Jones is some where in a level at least that's what my cousin said. And the right level is in the last crusade and the level is rescue professor Jones :)
Lego star wars Lego star wars 2 Lego star wars the complete trilogy Lego batman Lego Indiana Jones Lego Indiana Jones 2 the choronicles of Narnia: the lion the witch and the wardrobe (warning you need a 100$ graphics card to play this for PC) the choronicles of Narnia: prince casian (i don't think you need a graphics card for this one) kung fu panda
if you go to cheatcc.com and type in "Lego batman cheats for(psp,ps2,ps3,ds,wii or whatever console you have) they have heaps of cheats.
There is Elsa (Last Crusade), Henry Jones (Last Crusade), Brody (Last Crusade), Belloq (Raiders of the Lost Ark) and some more that I can't remember.
Ever single Lego game, you can get on the Xbox 360 but in case you don't know all the Lego games here they are: Star Wars Indiana Jones Batman Harry Potter Pirates of the Caribbean I may have left some out that I didn't know of but I am not big into Lego games.
Parcels are hidden in secret areas throughout the game that you normally have to use free play in order to get. However, some are out there in the open that are easily obtainable.
EVILR2
Indiana Jones is rated PG-13 for violence and some swearing.
there are tons of chests which one are you talking about?? besides they're all over the place and some you have to go back to the levels for because you need tiny people