Calculating Inventory and Costs to Support a Budget

Part 1: Lesson Description

Calculating Inventory and Costs to Support a Budget


This lesson will focus on applying basic math skills to determine current inventory on hand at a business or in the home, and calculate the number of items needed.  In addition, learners will determine the costs to replace items and apply the amount to an overall budget.

Learner Audience/Primary Users

Adult learners that are looking to apply basic math skills to supporting a budget will benefit from this lesson.

Educational Use

  • Curriculum/Instruction
  • Professional Development



Material Type

  • Instructional Material
  • Homework and Assignments
  • Interactive


  • Designers for Learning
  • Adult Education
  • Budget
  • Math

Time Required for Lesson

The estimated time for this lesson is one hour.

Targeted Skills

  • Calculating inventory
  • Determining replacement inventory
  • Identifying replacement costs
  • Comparing costs to budget
  • Ordering supplies

Learning Objectives

By the end of this lesson, the learner should be able to:

  • Calculate current inventory of in-stock supplies
  • Determine quantity of replacement supplies to order
  • Calculate costs of supply order 

College & Career Readiness Standards (CCRS) Alignment

  • Level: Adult Education
  • Grade Level: C
  • Subject: Mathematics
  • Domain: Math-Number and Quantity, and/or Reasoning with Equations and Inequalities
  • Standard Description
    • Generalize place value understanding for multi-digit whole numbers.
    • Use place value understanding and properties of operations to perform multi-digit arithmetic.
    • Perform operations with multi-digit whole numbers and decimals to hundredths.
    • Compute fluently with multi-digit numbers and find common factors and multiples.
    • Use the four operations with whole numbers to solve problems.
    • Write and interpret numerical expressions.

Prior Knowledge

The learner should have basic addition, subtraction, and multiplication skills prior to starting this lesson.

Required Resources

Instructor Lesson Guide

Handouts: Calculating Inventory Handouts file below, which includes Inventory Sheet sample, Inventory Sheet Class Activity, and Inventory Sheet Assignment 

Download: Calculating Inventory Handouts_aeBGjAe.xlsx

Calculator (if available)

Blank paper or notebook paper may be used for manual calculations if necessary

Lesson Author & License

Creative Commons License

Lesson Author: Heidi Saucier

License: Creative Commons License; Creative Commons CC BY 4.0 license (
Calculating Inventory and Costs to Support a Budget by Heidi Saucier is licensed under a Creative Commons Attribution 4.0 International License.)

Part 2: The Lesson

Instructional Strategies and Activities


Time: 5 minutes

Ask learners the following questions to determine previous experience in determining inventory:

  • How many of you have ever had to take inventory on specific items at home or work?
  • What were the items you took inventory on?
  • How did you count or track the items?
  • Did you ever have determine if anything needed to be replaced from that inventory?
  • How did you do that?
  • How many of you currently keep track of a budget at home or work?


Time: 5 minutes

Today, we are going to use addition, subtraction, and multiplication to show you how to keep track of items you might need to have available at home.  We will learn how to determine what items are on hand, how many more are needed, and what the costs are to replace those items.  Finally, we will compare those costs to a current budget.  After the lesson, you will have an assignment that will allow you to apply this lesson at home for the next week.


Time: 15 minutes

  • Instructor will display example inventory items at the front of the class if available
  • Instructor will pass out a sample inventory sheet to the class
    • Note: Instructor may adjust prices on sample sheet to reflect most current prices for items
  • Instructor will document on chalkboard/dry erase board in order to demonstrate
    • Counting inventory
    • Determine inventory needed
    • Determine costs
    • Calculate total funds needed to replace inventory
    • Compare total funds to current budget
  • Instructor will repeat process, asking learners to call out steps to review learning

Guided Practice

Time: 20 minutes

  • Instructor will pass out handout with new inventory details to class
    • Note: Instructor may adjust prices on sample sheet to reflect most current prices for items
  • Learners will work in pairs for guided practice activity
  • If there is an uneven number of learners, one group may work as a trio
  • Using the principles learned during the presentation activity, learners will work together to do the following:
    • Count inventory
    • Determine inventory needed
    • Determine costs
    • Calculate total funds needed to replace inventory
    • Compare total funds to current budget
      • Instructor will assign each group a different budgeted amount, starting at $30
  • Instructor will rotate between groups to monitor progress and provide feedback and assistance as needed


Time: 10 minutes

Instructor will ask learners the following questions:

  • How did you calculate the total funds needed to replace the inventory for the items on your list?
  • How did those funds compare to the budget listed on your handout?
  • What challenges did you face as you determined the inventory needed and the costs to replace those items?
  • If you were missing information, such as the cost to replace the item, how might you find that information?


Time: 5 minutes

  • Instructor will hand out application assignment sheet
  • Instructor will explain details of assignment to learners
  • Learners will choose between two and four items that they want to track inventory of at home
  • Examples could include toilet paper, gallons of milk, dish soap, toothpaste, etc.
  • Using the assignment sheet, learners will document the number of items currently on hand, and home many of each item is needed to allow for two weeks of use
  • Learners will also document the cost of each item, then calculate the total cost to replace the item
  • Learners will determine how much money they will need to budget out to replace the chosen items
  • Learners will return completed assignment sheet to class within two days and be prepared to share their findings with the class
Return to top