Cash received from customers includes all $139,000 of the accounts receivable that were outstanding at November 30, 2017. Accounts receivable at December 31, 2017 totaled $141,000.

Accounts payable (to suppliers of inventory) decreased by $19,000 from November 30, 2017 to December 31, 2017. The balance in the inventory account decreased by $39,000 over the same period.