In the ACCA F7 exam, you'll have to describe and apply the principles of inventory valuation. IAS 2 Inventories is the accounting standard which covers this, here's a little summary.
Scope of IAS 2 Inventories
Inventories are covered by IAS 2 Inventories, and there are three methods of valuing or measuring the cost of inventory allowed. These are
First in, First Out ('FIFO')
Weighted Average Cost
What Method Should you use...