Glad to have you here in the Community, @maggie9.
If an amount (30.00) isn't included in a bank statement, I recommend checking on your financial institutions' website to verify if the transaction has been cleared already. If so, download it, if it's not, you may add it to your next reconciliation.
When it comes to the discrepancy on your account, I suggest reviewing the transactions that are part of your current reconciliation to verify if there are entries that have been included and are not listed on the statement.
Another factor that you need to consider which may lead to a discrepancy are a change from prior reconciliation. I've got here a link that you can refer to regarding the complete details on how to fix reconciliations issues such as discrepancies: Fix issues when you're reconciling accounts in QuickBooks Online
You may also see this resources below to learn more about reconciling accounts in QuickBooks:
If there's anything else that I can assist you with, let me know. I'm always here to help. Take care!
