If the bank mistakenly deducts a check from an account would I be adding or subtraction the amount in the bank reconciliation under the balance per books section?

If the bank mistakenly deducts a check from an account would I be adding or subtraction the amount in the bank reconciliation under the balance per books section?

You would list as a reconciling item - Bank error and add it to your book balance to rec to your account balance. Then you call the bank and get your money back :)