ESTIMATION ACTIVITIES: Engage in estimation activities to improve estimation and prediction skills.

learning skilLS

Sustained Attention

Working Memory

Flexibility

instructional strategy
Estimation Activities

Engage in estimation activities to improve estimation and prediction skills.

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LEARNING PREFERENCES

academic skill

Grade 5-7

Decimals: Solve problems involving whole numbers and decimal numbers to calculate retail prices and check calculations.

Grade Curriculum Focus
5Solve problems involving whole numbers and decimal numbers, including those requiring more than one operation, and check calculations
6Solve problems involving the addition and subtraction and rounding of whole numbers and decimal numbers, using estimation
7Understand and recall commonly used percents, fractions, and decimal equivalents

Lesson Objective, Goal and Success Criteria

  1. Learn how to accurately subtract whole numbers, and money amounts, with decimals up to hundredths and percentages.
  2. Learn how to check calculations, by reversing the operation.
  • Accurately subtract whole numbers and decimals up to hundredths, and correctly write the answer using dollar signs and decimals.  
  • Demonstrate the ability to use the answer to “add and check” the work.
  1. The student is able to correctly write the monetary amounts, using the dollar sign and decimal point, in the correct locations.
  2. The student is able to consistently subtract the smaller number from the larger number, rather than reversing the numbers.
  3. The student accurately uses their answer to “add and check” their work.

UDL Instruction

Full Class warm-up activity: The teacher starts the lesson with a review of adding and subtracting money amounts. This activity involves participation of several students in the class as follows:  

Step 1:  The teacher asks 3 students to volunteer to come to the front of the class then asks each student to:
  1. Use a tablet or other device to Google the price of an item they would buy if they had $100.
  2. Write the name of or draw a picture of the item on the board (using the grid in supplemental resources).
Step 2:  The teacher asks another 3 students to come to the front and asks each student to estimate the price of one of the 3 items (each picks a different item). They write this price in the estimated price box on the grid.

Step 3: The first 3 students then record the actual price of each of their items in the actual cost boxes of the grid.

Step 4:  The teacher asks the class how they can find out “how close” they were to the real price, and “eventually”, the idea of subtracting the smaller number from the larger number is agreed upon.   The teacher then demonstrates how to:
  • Subtract each of the estimated costs from one another including which number goes on top. 
  • Verify each calculation with addition
  • Determine which student made the closest estimation. 

Differentiated Instruction

Paired/Small Group Activity: The class is divided into 2-3 students in pre-determined small groups to mix up ability and grade levels. All students will have access to one of two shared Google slide decks. Half of the class will develop the first slide deck and the second half of the class will create the second slide deck.  Each group creating a slide deck will own 1 slide they create as follows:
  • Each group will put their names at the top of the slide
  • Each group will use a tablet to find an item they wish they could buy up to $9000
  • They copy and paste an image (only) of the item on their slide. 
  • Do not place the price, title or any other identifying labels of the item on this slide. 
Items could include students’ interests, board games, video games, popular clothing items, candies/treats, books, sporting goods, collectibles, etc.  

As an alternative to using the internet, the students can use local flyers from popular stores in the neighbourhood. As an alternative to Google slides/ipad/tablet, the groups can also draw their items on easel paper or a class board.

Pair/Small Group Estimation of Prices: This activity enables each student in the pair/group to support each other in problem solving. Since estimating the price of an item is not necessarily dependent on a specific Math skill, students of all ability levels can participate equally on that portion of the activity. 

Estimation Slides: Each group of 2-3 students will have a  Google slide to keep track of their estimations and calculations of each presented item. A sample of this slide is included in the supplemental resources.

One group from each of the two slide decks will simultaneously present the item they selected to the rest of the students and ask them to estimate the price of the item. Students not currently presenting will estimate the prices of items presented from slide deck they DID NOT USE for the creation of their items so they do not have the opportunity to look at these items in advance.
  1. The students will use their Google slick tracking table to first record the estimated price of each item presented. 
  2. The group who selected the item will record the actual price of the item on the slide beside the item and present it to the group again. 
  3. Students will identify how close their estimate is from the actual item by subtracting the estimated price from the actual price.
  4. They will verify their subtraction calculation through reverse addition.
  5. The teacher will highlight the 2 groups with the price closest to the actual price
    1. Group with closest estimate receives 10 points
    2. Group with second closest estimate receives 5 points
    3. All other groups get 2 points each for participation
Teacher Guidance: Make sure the students understand that the smaller number must go “underneath” the larger number to subtract. Remind students about how to use $ and decimals to write down their answers. Also review the term “estimation” in the context of what they are doing. The teacher asks students to complete the first question and circulates to offer help as needed.

Teacher Tip: Support students as needed and remind students that the answer is equal to the number they started with, if they subtracted correctly.

Measurement of Success

Class Discussion: The estimation totals of each item are shared with the entire group and points are awarded using reward sheet as follows:
  • 10 points to the group with the closest estimate to actual cost (lowest subtracted value) 
  • 5 points to the group with the second closest estimation
  • 2 points to all other groups
  • 0 points are recorded if the question is not completed.
The pairs/groups add up their points and the group with the highest score wins a small prize (there may be multiple winning winners).

The teacher asks the group what they learned from this activity. Responses could include:
  • Estimations of prices can vary a lot
  • It is important and easy to verify final calculations

Materials, References and Resources

Tablets or IPads- $0 assuming class has access to these resources already.

Projector and Screen

Lynch, Matthew. (2023). Activities to Teach Students to add and Subtract Money Amounts Activities to Teach Students to Add and Subtract Money Amounts – The Edvocate (theedadvocate.org)


Miacademy Learning Channel-How to Add and Subtract Money

https://youtu.be/EPdkGwXjf7c?si=LHN7jZ7-5QXVH_Pl

Subtracting: Regrouping From Zero- Khan Academy

Resource #3 and website or video link if applicable

Supplemental Documents

Worksheets:

  • Warm-Up Activity
  • Estimation Tracking Sheets
  • Closest Guess Score Sheets
Estimation-Activities-Worksheets-Math-Decimals-Grade-5-7-1Download

Google Slide Retail Items

Google Slide Deck #1

– Link to the Google Slide Deck #1

Google Slide Deck #2

– Link to the Google Slide Deck #2