I needed to cross 3 bridges, the toll at each bridge was half my eggs plus half !

I needed to cross 3 bridges, the toll at each bridge was half my eggs plus half an egg.?

I paid at each bridge without breaking any eggs and ended up with none, How many eggs did I start with ?

7 eggs.

1st bridge: 4 eggs (1/2 of 7 is 3.5 plus .5 eggs = 4)
2nd bridge: 2 eggs (1/2 of remaining 3 is 1.5 plus .5 eggs =2)
3rd bridge: 1 egg (1/2 of remaining 1 is .5 plus .5 eggs = 1)