B2.7 Multiply and divide integers, using appropriate strategies, in various contexts.
Activity 1: Finances (Operations on Integers)
Divide the class into teams of 4 students.
Each team will receive situations related to finances.
They have to find the mathematical expressions and the solution to each problem.
The solution must include a detailed explanation (may be in the form of an expression or equation). Take pictures of 2 or 3 approaches.
Ask team members to explain them to the class.
Examples of situations
- After completing an activity, five friends realized that they had run up a $40 deficit. They decided to divide the debt so that they would each put in the same amount, bringing the account to zero. Illustrate each person's debt with a mathematical expression.
- A business loses $150 each month. Calculate the deficit after 11 months.
- A house has an initial value of $280 000. Six months later, its value increases by $32 000. However, for the next two years, its value decreases by $14 000 every 6 months. What expression represents the new value of the house? Find this new value.
- A new scooter sells for $7550 with taxes. Its value decreases by $875 per year for the first 6 years. What mathematical expression represents the new value of the scooter? What is this value?
- Olivia has $750 in her savings account. During the holidays, she makes 3 withdrawals of $75 and 2 deposits of $25. At the end of the holidays, she decides to make a donation to charity. The amount of the donation is one fourth of her balance. What mathematical expression represents Olivia's banking transactions? What is the new account balance?
- Three friends share a debt of $900. What mathematical expression represents one person's debt? Identify this debt.
Activity 2: The Table (Multiplication and Division of Integers)
Materials
- whiteboard
- erasable marker
Prepare a PowerPoint with a series of small mathematical expressions containing negative integers. Project one expression at a time. The student solves the problem and writes the answer on the whiteboard. After a few seconds, ask the student to raise the board. Check the answers.
Examples of expressions
- \({}^ - 4\; \times \;{}^ - 6\)
- \(\frac{{{}^ - 24}}{{{}^ - 8}}\)
- \({}^ - 9\; \times \;3\)
- \(\frac{{{}^ - 36}}{9}\)
- \({}^ - 4\; \times \;{}^ - 6\; \times \;{}^ - 3\)
Problem
The temperature dropped by two degrees Celsius on each day last week. Calculate this temperature drop.