[wrycoder]

It's usually expressed as

Assets + Expense = Liabilities + Equity + Income

The two accounts on the left normally carry a debit balance, and three on the right normally carry a credit balance.

At the end of the accounting period, subtract the Expense balance from both sides of the equation, and close out (Income - Expense) into Equity, i.e. if that was positive, Equity increases.

Or, in a computerized system,

Assets + Expense - Liabilities - Equity - Income = 0