A comprehensive guide to understanding and calculating trading profits and applying trading loss reliefs for businesses in a tax context. The first source details the calculation of trading profits, distinguishing them from income and capital profits, and explaining the formula which involves chargeable receipts, deductible expenditure, and capital allowances such as the Annual Investment Allowance (AIA) and Writing Down Allowance (WDA). The second source outlines various methods for an unincorporated business to offset a trading loss, including Startup Relief for early-stage losses, Carry-Across/One-Year Carry-Back Relief against total income, and Carry-Forward Relief against future profits. Additionally, the second source explains specific relief options for incorporated companies, noting key differences like the use of total profits and different claim deadlines for loss carry-backs, including relief for terminal trading losses when a business ceases operation.