Notes Receivable explanation, calculation, historical data and more. Receivable (AR) icon next to the contract.We're going to walk you through how to calculate accounts receivable in this guide. We'll demystify a myriad of different formulas and ratios you need to know. Consumers' Accounts Receivable - Operating Section. Middlesex University Students' Union (MDXSU). The business was formed in 2008 and today is one of the largest independent specialists serving over two million participants nationally in the K-12 market. Accounts Receivable. (466). 571. Unbilled Revenues. (2,361). (740).