The student will understand and explain inventory and the
importance of inventory tracking.
The student will calculate ending inventory for school store
items using beginning inventory, sales, and order
The student will determine which items need to be re-ordered
based on the store’s inventory goals and policy.
Connection to Bloom’s Taxonomy
- Crayons or Colored Pencils
- Index Cards
- Worksheets for lesson plan 9 (see sidebar)
Ask students to define the word inventory. As a class,
brainstorm some possible definitions for the word. Before you
give the students the definition, discuss Hannie’s Word Origin
and have the students make up their own working definition.
Next, ask if anyone has ever visited a store that was in the
middle or about to start taking an inventory? Explain that
stores often bring in extra employees to help count every item
in the store. Sometimes you may see tags with numbers indicating
store stock numbers and maybe even the number count for
different items. Inventory is a list of goods, materials, or
items that a store has in stock. In a store setting, this is a
list of items that a shop has available to be sold.
It is important for store owners to know their inventory. As a
class, brainstorm several reasons why tracking inventory is
Some possible responses may include the following:
To have the right items available when customers want them
To track when items numbers are becoming low and need to be
To reduce expenses associated with holding onto items that do
not sell and are not popular
To understand what items people want or need and what items
people are not interested in purchasing
- To plan for future purchases when stocking shelves
To determine what items should be marked down in price for
quicker sale and to free up shelf space for items in demand
To have a good reputation as a store that always has items in
Explain to students that inventory can be tracked for many
different items not just store items. Pair students together and
ask them to conduct an inventory of the items in the classroom.
Classroom Inventory (PDF)
as a transparency or worksheet to help guide students. Ask the
students why it is important for a teacher to know the inventory
of items in his or her classroom. Discuss that tracking
classroom items may help the teacher determine if supplies are
getting too low or if there are enough supplies for every
Exploring and Learning
At Home Assignment: Tracking inventory occurs
all around us. Prior to starting this lesson in class, ask
students to interview several family members about what types
of items they keep track of at home. Students should explore
what type of inventory tracking takes place within a home.
They should also find out what family members track on a
weekly, monthly, or even annual basis? Have student’s record
answers and be prepared to share those responses the next day.
As a class, have students share responses from the “At Home
Assignment”. Responses will vary and may include the
Food in the refrigerator: cartons of milk, eggs, yogurts
(shopping list for groceries)
Paper goods - napkins, paper plates, paper cups, plastic
spoons, toilet paper
- Dry goods – cereal, granola bars
- Clothing – socks, underwear, t-shirts
- Baby supplies - diapers, baby formula, wipes
- Cleaning products - soap, glass cleaner sponges
Personal care products – cotton swabs, dental floss,
First aid supplies – bandages, pain relievers, cold packs
- Gardening supplies – grass seed, fertilizer
Collections – CDs, baseball cards, coins, DVDs, computer
Arts & crafts supplies – paper, crayons, markers,
Office supplies – printer cartridges, pens, pencils,
Tracking inventory can be easy or quite complex. At home,
family members generally keep track of items used and that
need to be replaced by counting or estimating. For example,
your may notice that there is only one roll of paper towels
left on the shelf. If you are planning several cleaning
projects – all the house windows and storm doors, the mirrors,
the patio furniture, and the car, you will need to estimate
how many additional rolls to purchase. You may choose to buy
three rolls, which means you would have a total of four rolls.
If you use two rolls on the cleaning project, there will still
be two rolls on the shelf for additional use.
Explain to students that tracking inventory is an important
part of operating a school store. Using the class computer,
visit the Raymond Geddes website. If a
computer is not available use a Raymond Geddes catalog or any
office supply store catalog or sales brochure. As a class,
browse through the website or catalog. Ask students to
identify some general categories of products the company
offers to school stores? Examples from the assortment of
Raymond Geddes school store items may include the following:
- Geddes Exclusives (Planet Happy, Dr. Seuss, etc.)
Writing Supplies (pens, pencils, mechanical pencils, and
School Supplies (bookmarks, calculators, erasers, pencil
grips, sharpeners, stretch book covers, etc.)
Art Supplies (colored pencils, crayons, markers, scissors,
Paper Supplies (folders, memo pads, paper and notebooks,
Toys and Gifts (candy, cell phone accessories, key chains,
toys and games, wearables)
Holiday Supplies (Halloween, Christmas, Winter, etc.)
Carded Supplies (supplies packaged with cardboard to fill
card racks or pegboards)
Clearance Deals, Weekly Specials, New School Supplies,
Party Favors, etc.
Discuss the fact that even though a school store may seem like
a small enterprise compared to a large department store, the
level of inventory can be detailed. Review the following
information with students:
Items may be small and numerous and keeping track of those
items is still as important as tracking the large items.
Part of running a school store is maintaining inventory
control. Inventory control includes purchasing items,
caring for or storing the items, and selling the items.
The goal of good inventory control is to ensure that there
is an appropriate supply of items at all times – not too
much and not too little.
Ending inventory is determined by subtracting sales
(reduces inventory) and adding orders (increases
Present students with the following scenario:
RG and Hannie are working at the Raymond Geddes Elementary
Bookstore. Sniffer has asked them to track inventory for
Can you help RG and Hannie determine the ending inventory
amounts for the school store?
To help complete the scenario, pair students together and
provide each group with the following:
The next activity can be completed together as a class by
using guided practice to complete each step of the process.
You may choose to to have the worksheet as class and the other
half independently. Explain and guide students through the
Step 1: Using the
School Store Sales Worksheet (PDF), find out how many of the following pencils were sold
during the week. Add up the number of each pencil sold per
day and record the total:
( 1 + 4 + 6 + 5 + 4 = 20 )
Pet Silhouettes Pencils
( 2 + 3 + 0 + 5 + 3 = 13 )
Astral Wonders Pencils
( 5 + 3 + 2 + 1 + 3 = 14 )
Step 2: Using the
School Store Beginning Inventory Table (PDF), fill in Column A on the
School Store Ending Inventory Record: Friday (PDF). If your class has access to a school store, you can
have students list and count actual items in your store on
a given day.
Retro Pencils ( 20 )
Pet Silhouettes Pencils Pencils
( 20 )
Astral Wonders Pencils
( 35 )
Step 3: Next, complete Column B on the
School Store Ending Inventory Record: Friday (PDF) by
entering the numbers that you added up back in Step 1.
- 20 Retro Pencils
- 13 Pet Silhouettes Pencils Pencils
- 14 Astral Wonders Pencils
Step 4: Complete Column C on the School
Store Ending Inventory Record: Friday (PDF) by filling in
the number from the
School Store Orders (PDF)
column titles Total Items. Explain that the total items
number is the number of items originally order from
72 Retro Pencils
( 20 - 20 = x )
72 Pet Silhouettes Pencils Pencils
( 20 - 13 = x )
72 Astral Wonders Pencils
( 35 - 14 = x )
Step 5: Calculate the ending inventory
totals for each item listed on the School Store Ending
Inventory Record: Friday. Subtract total sales from the
beginning inventory and then add any school store orders
that arrived during the week.
72 Retro Pencils
( 20 - 20 = 0 + 72 = 72 )
72 Pet Silhouettes Pencils Pencils
( 20 - 13 = 7 + 72 = 79 )
72 Astral Wonders Pencils
( 35 - 14 = 21 + 72 = 93 )
As a class, review the results. Refer to the
Product Analysis Worksheet Answer Key (PDF)
Sales Analysis Worksheet Answer Key (PDF)
Discuss the following sales analysis questions:
Which day of the week generated the most sales?
Which day of the week generated the least sales?
What was the range between the highest sales day and the
lowest sales day? ($14.76)
Brainstorm some possible reasons to explain why sales on
Friday were so much better than sales on Monday for this week.
Some possible explanations include the following:
Students may not remember to bring in their money when
returning back to school after the weekend.
The school may be able to send out more reminders during
the week advertising the school store and its products.
Teachers may have completed their lessons with students
providing students more time at the end of the week to
shop at the school store.
Students purchased more of the most expensive item
(6-Color Pens) on Friday. This may have helped to boost
sales for the day.
There may not be any particular reason since we have only
one week’s worth of sales. Students would need multiple
weeks of sales results to determine if Friday always
remained the best day of the week.
Review the definition of statistics—collecting, organizing,
and interpreting data. Do students feel they were successful
using statistics to analyze product and sales data?
Lead a short discussion on some of the shortcomings of
statistics. Statistics can be helpful to analyze data.
However, statistics may also be misleading. As shown above,
students cannot pinpoint the exact reasons why Friday
generated the highest sales for the week. Statistics do not
take into account the human factor - why people make the
decisions they do. Averages, in particular, can be misleading.
They may be affected by outliers, extreme high and low values.
Often times, mathematicians will drop the highest and lowest
values in a sample in order to arrive at a more representative
Extended Learning and Practice
Spend more time analyzing the
Weekly Sales Results Excel Spreadsheet.
What was the average daily number of items sold for the
( 656 ÷ 5 = 131 items )
What was the median number of daily items sold?
( 134 items )
What was the range?
( 148 - 105 = 43 items )
PBS Kids ZOOM website
for another in-class activity to calculate averages. How heavy
are your students’ backpacks? Collect, organize, and calculate
data just like ZOOM did.
The lesson objectives can be assessed by evaluating the
Weather Data Worksheet (PDF), the
Product Analysis Worksheet (PDF), and the
Sales Analysis Worksheet (PDF)
Weather Data Worksheet Answer Key (PDF), the
Product Analysis Worksheet Answer Key (PDF), and the
Sales Analysis Worksheet Answer Key (PDF).
Assessment of Student Progress PDF
to assess students’ overall abilities to meet the lesson’s
learning objectives, which include analyzing product price and
sales data by calculating mean, median, mode, and range; and
understanding how statistics are used to collect, organize, and
Provide each student with an index card and have them answer the
following questions on one side of the card:
What are two new things that you have learned?
What else would you like to learn about this topic?
On the back side of the index card, instruct the students to
draw a picture of something they learned about during this
lesson. The index cards can be hole punched and held together
with a simple shower curtain ring.