Guesstimating Groceries: Adding and Multiplying Money
Sioned Seeley-Cavers & Laurel Apps
Grade: 5
Curricular Competencies:
● Estimate reasonably
● Develop mental math strategies and abilities to make sense of quantities
● Model mathematics in contextualized experiences
● Develop, demonstrate, and apply mathematical understanding through play, inquiry, and
problem solving
Curricular Content:
● decimals to thousandths
● addition and subtraction facts to 20 (extending computational fluency)
● financial literacy — monetary calculations, including making change with amounts to
1000 dollars and developing simple financial plans
Introduction
The learning object that we created is grocery game called Guesstimating Groceries. The
purpose of Guesstimating Groceries is to work on addition fluency and estimation with a real-life
application. In the game, students are given a shopping list of food items and a $20 budget (see
Appendix 1). Each student will have a different grocery list, with its own set of items and total
cost.
Actual objects of food items will be scattered around the room with their costs written or glued
on underneath. For teachers first playing this game, or teachers who do not have actual items,
pictures work as a good substitute (see Appendix 2). Students will take their lists and walk
around the room, finding the items and the prices of each. Then, using addition and any other
strategies the students have, they will estimate if they have enough money to buy all the items
on the list. Teachers can provide monopoly money, or other manipulatives to help students
estimate if they have enough money in their budget to buy all their list items. Students can
collaborate with each other and share strategies while working, but each student will come up
with their own estimation for the total cost.
After each student has gathered all the prices on their grocery list, and has had an opportunity
to come up with a total, the students will come together as a class to debrief. It is important to
include the debrief portion of this activity, as it allows all of the students to hear and share the
strategies that some may not have considered prior.
Nowadays, there is less of an emphasis on finding exact numbers and more emphasis on being
able to use strategies to find nearest approximations. We wanted a game that included
differentiated learning and allowed children to use a variety of strategies that work best for them
in order to problem solve, while working on the same task. Additionally, we wanted to create a
game that was applicable to real life, engaging, and playful. Play is often overlooked for grade 5
students, yet allows children to use their creativity while developing their imagination and
encourages critical thinking and problem solving skills.
The target grade level for our activity is grade 5. However, the game could easily be adapted to
younger or older grade levels depending on mandated curricular content and ability of class. We
have also included strategies for adaptations below. We chose these grades because decimals,
addition, and financial literacy are important components of the grade 5 math curriculum. This
activity will also help students practice mental math strategies, estimating reasonably, and
develop mathematical understanding through play, inquiry, and problem solving.
Adaptations and Extensions:
Lists & Budgets: Lists and budgets could be made smaller/larger depending on students’
understanding and competence of the learning outcomes. Budgets can also be adjusted based
on the context and story behind the game (eg. if students are purchasing for a restaurant the
budget might be increased to $1000.00, verse a single family home where the budget might be
$100.00).
Prices: If students aren’t ready to work with decimals, prices can be written as whole numbers
(eg. $2.00 or $2 rather than $2.75)
Visual Aids: Pictures of items can be printed with the dollar amount represented by coins and
bills, base 10s, or counting blocks.
Multiplying: Students who are fluent in addition can try multiplying like costs (eg. if there are
multiple items on the list that are $3.50)
Estimating: If students have determined that their list budget would need to be under or over
$20, students could work out how much money they would have left over or how much more
money they would need to buy all of their list items.
Adding Tax: For older grades, teachers may ask students to include tax in their estimates to
see whether students will still have enough money in their budget to purchase all items. (eg.
adding 10% or multiplying total x 1.10)
Coupons and Sales: To add complexity, teachers can offer coupons or sales on specific items
(eg. buy 2 get one free)
Health Education: Teachers can use this activity as an opportunity to discuss and compare the
prices of healthy eating choices and students could decide what items to take off their list if
their list is over their budget.
Assessment
Debriefing/ Discourse: Once everyone has had a chance to “buy” their groceries, debrief the
class on different strategies used, such as: addition of whole numbers, rounding decimals,
multiplication of like numbers.
Questions to Ask During Debriefing
○ How did you get the total? (addition, rounding, multiplication of like number)
○ Did you have enough money to buy all the items on your list?
○ How much money, if any do you have left over?
○ Which strategies were the fastest?
○ What strategy worked best?
○ What strategy was most accurate?
○ What items could you/ did you remove in order to meet your budget?
○ What items could you/ did you add to your list if you were under budget?
Checklist: While children are debriefing, teachers should make note of the different strategies
each student used during the game in order to assess the level of comprehension and fluency in
adding and estimating (see Appendix 3 for sample checklist).
Exit Slip: At the end of the lesson, the teacher will provide students with an exit slip for them to
write down one thing they learned, and any questions the students may have. The exits slips will
be collected by the teacher in order to help guide future lessons (see Appendix 4 for sample Exit
Slip)
Consult the following document for corresponding appendices. Guesstimating Groceries Adding and Multiplying Numbers