A bank customer had £100 in his account. He then made 6 withdrawals, totaling £. He kept a record of these withdrawals, and the balance remaining in the account, as follows:

Withdrawals Balance left
£50 £50
£25 £25
£10 £15
£8 £7
£5 £2
£2 £0
£100 £99


Why are the Totals not exactly right ?

Mismatch Sum Puzzle

There is no reason whatever why the customer's original deposit of £100 should equal the total of the balances left after each withdrawal.
The total of withdrawals in the left-hand colum may equal £100, but is is purely coincidence that the total of the right-hand column is close to £100.
Let us show another example, but starting with £200 in the bank:
Withdrawals Balance left
£50 £150
£25 £125
£10 £115
£8 £107
£5 £102
£2 £100
£100 £699
Moral of this story? Don't Total Balances.

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