Unit 7 • Lesson 20.8h

Inventory Cost Flow Foundations: Beginning Inventory, Purchases, and COGS

To teach the basic accounting logic of inventory movement before method comparison begins in Lesson 3. Students must understand that ending inventory value depends on cost assignment choices, not just unit counts.

What You'll Learn
  • Trace inventory movement through the ending inventory formula step by step
  • Distinguish between physical flow (units moving) and cost flow (value assignment)
  • Explain why ending inventory value is not obvious when the same product is purchased at different prices
  • Identify where mistakes commonly occur in inventory tracking
Key Concepts
Ending Inventory = Beginning Inventory + Purchases - Cost of Goods Sold
Goods Available for Sale = Beginning Inventory + Purchases
Physical flow tracks units on the shelf; cost flow tracks which dollars belong to sold vs. remaining inventory
+2 more concepts
Lesson Phases

This lesson follows a structured 6-phase learning model designed for authentic project-based learning.

Hook

Discover why ending inventory value is not obvious just from counting what remains on the shelf

Start Phase

Introduction

Learn how inventory moves through the formula and why physical flow differs from cost flow

Start Phase

Guided Practice

Walk through a simple inventory timeline by hand, tracking units available and units remaining

Start Phase

Independent Practice

Compute goods available for sale and identify what must be assigned to COGS versus ending inventory

Start Phase

Assessment

Check understanding of beginning inventory, purchases, goods available for sale, and ending inventory logic

Start Phase

Closing

Summarize the movement logic and preview Lesson 3 as the introduction of FIFO and LIFO

Start Phase
How You'll Learn
Hand-calculation first before any spreadsheet complexity
One shared practice dataset with dated purchases and sales
Clear separation of quantity tracking from value tracking