Additional Information: 1. The notes receivable, along with any accrued interest, are due on November 22, 2022. 2. The notes payable are due in 2025. Interest is payable annually. 3. The investment in debt securities consist of treasury bills, all of which mature next year. 4. Deferred revenue will be recognized as revenue equally over the next two years. Required: Determine the company's working capital (current assets minus current liabilities) at December 31, 2021