We Distribute, Yet Things MultiplyClass 8 Mathematics Case Study Questions
10 Questions
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Case 1 of 10
Case Study7 marks
The Community Garden Expansion
A community group manages a rectangular vegetable garden. Initially, its length is meters and its breadth is meters. The gardeners decide to expand the plot to grow more vegetables. They increase the length by meters and the breadth by meters. The original dimensions of the garden were m and m. The planned expansion is to add m to the length and m to the breadth. The group wants to use algebraic identities to calculate the new area and understand the increase in size, just like in their mathematics textbook.
Questions on this case
1(1 mark)MCQ
Which of the following expressions represents the new area of the garden after expansion?
2(1 mark)
What are the new dimensions (length and breadth) of the garden in meters?
3(1 mark)MCQ
Using the distributive property, the expansion of is . What does the part represent?
4(2 marks)
Calculate the increase in the area of the garden in square meters.
5(2 marks)
If the expansion was instead a decrease of m in length () and an increase of m in breadth (), what would be the change in area?
Case Study7 marks
Designing a Square Park
An architect is designing a large square park with a side length of units. Inside this park, she plans to create a smaller square floral garden, also centered, with a side length of units. The area between the outer park boundary and the inner floral garden will be a paved walkway. The architect wants to find an efficient way to calculate the area of this walkway using algebraic identities. For a specific project, the park has a side length of meters, and the floral garden has a side length of meters.
Questions on this case
1(1 mark)MCQ
Which expression represents the area of the paved walkway?
2(1 mark)MCQ
The identity can be factorized. What is its factorized form?
3(1 mark)
Using the identity , calculate the area of the paved walkway with the given dimensions ( m, m).
4(2 marks)
Now, calculate the area by first finding and individually and then subtracting. Show your work.
5(2 marks)
If the walkway has a uniform width , express in terms of and . Then, write a new expression for the walkway's area only in terms of and .
Case Study7 marks
The Bakery's Quick Calculation
A baker sells muffins for ₹11 each. At the end of the day, he needs to quickly calculate the total revenue from selling a large number of muffins without using a calculator. He remembers a method from his school mathematics class for fast multiplication by 11. The method involves using the distributive property, where multiplying by 11 is the same as multiplying by . For example, to calculate the revenue from selling 387 muffins, he needs to find the product .
Questions on this case
1(1 mark)MCQ
Using the distributive property, how can be rewritten?
2(1 mark)
Calculate .
3(2 marks)MCQ
The one-line method for multiplying a number 'dcba' by 11 gives the result 'd (c+d) (b+c) (a+b) a', with carries. For , the result is 42614. What is the product of ?
4(1 mark)
The baker also sells special cakes for ₹101 each. Using a similar distributive method for , calculate the revenue from selling 89 cakes.
5(2 marks)
On a discount day, the baker sells a special bread for ₹99. He sold 23 loaves. What is the total revenue? Use an identity to calculate this mentally.