B2.4 Add and subtract integers, using appropriate strategies, in various contexts.
Activity 1: Operations Bowling (Addition and Subtraction of Integers)
Materials
- 1 green die (positive integer)
- 1 red die (negative integer)
- paper bag
- worksheets with boxes to fill in
Individual work
Prepare one worksheet per student. The student places the two dice in a paper bag, randomly picks one, and then rolls it on the desk. The green die represents a positive integer and the red die represents a negative integer. The student should now fill in the boxes from left to right and then solve the mathematical expression. Possible extension: have students choose where to place each integer to create the maximum or minimum possible value.
Examples of Expressions to Fill in on the Worksheet
- Sheet 1:
- Sheet 2:
- Sheet 3:
Activity 2: The Thermometer (Operations on Integers)
Divide the class into subgroups of three people. Distribute a worksheet with the chart below. Each group must answer the questions and demonstrate their work. Circulate and check students' strategies.
Recommended Materials
- a thermometer
- a blank number line with erasable felt-tip pen
| Cities | Average Low Temperatures in
January |
Average High Temperatures in
July |
|---|---|---|
| Vancouver, BC | 0 °C | 22 °C |
| Edmonton, AB | \( - 19\;^\circ {\rm{C}}\) | 23 °C |
| Yellowknife, NT | \( - 31\;^\circ {\rm{C}}\) | 21 °C |
| Winnipeg, MB | \( - 23\;^\circ {\rm{C}}\) | 26 °C |
| Ottawa, ON | \( - 15\;^\circ {\rm{C}}\) | 26 °C |
| Toronto, ON | \( - 10\;^\circ {\rm{C}}\) | 27 °C |
| Montreal, QC | \( - 14\;^\circ {\rm{C}}\) | 26 °C |
| Halifax, NS | \( - 9\;^\circ {\rm{C}}\) | 23 °C |
| St. John's, NL | \( - 7\;^\circ {\rm{C}}\) | 20 °C |
Sample Questions
- Using a number line, demonstrate the strategy to determine the temperature difference between the lowest temperature in January and the highest in July in Edmonton, Montreal, Yellowknife, Toronto and Vancouver.
- What do you notice about the differences?
- What is the greatest temperature difference between cities in January? Name the cities used.
- What is the smallest temperature difference between the cities in July? Name the cities used.
- What is the average of the highest temperatures of the cities listed in the table?
- What is the average of the lowest temperatures of the cities listed in the table?
- What is the difference between these two averages?
Note: It might be helpful to have a giant thermometer built on the floor where the student could move around to find the answers to the questions.