Bank Balance

	1) Your friend places a few pennies on a plate and counts them aloud (nine cents, let  say in this case).
2) He then “spends” some of the pennies (say 4 cents) by dropping them in a small envelope (“The Shop”) which is then sealed up.
3) The remainder are poured  into a large envelope (“The Bank”) which is sealed firmly and guarded by a member of the audience.
4) The small envelope is placed on the plate and is burnt.  The four “spent” pennies have vanished.
5) The person guarding the “Bank” then tears open the large envelope and tips the coins out. The original sum (9 cents) is there, plus an extra penny – interest.