B1.5 Round decimal numbers, both terminating and repeating, to the nearest tenth, hundredth, or whole number, as applicable, in various contexts.
Activity 1: The Currency Converter
Present the following problem to students:
Using a currency converter, I get the following amounts:
- 1.00 Australian dollar = 0.967 Canadian dollar
- 10 Japanese yen = 0.114 Canadian dollar
- 20 Moroccan dirhams = 2.79 Canadian dollars
- 1.00 US dollar = 0.795 Canadian dollar
Round each amount to the nearest hundredth and unit.
Allow students to use the strategy of their choice to solve the problem.
Example
Round to the nearest hundredth and to the nearest unit
- 0.114 rounded to the nearest hundredth is 0.11.
- 0.795 rounded to the nearest hundredth is 0.80.
- 0.967 rounded to the nearest hundredth is 0.97.
- 2.79 is already rounded to the nearest hundredth 2.79.
- 0.114 rounded to the nearest unit is 0.
- 0.795 rounded to the nearest unit is 1.
- 0.967 rounded to the nearest unit is 1.
- 2.79 rounded to the nearest unit is 3.
Select a few students to present their solution. Allow students to review their work.
Activity 2: The Vet and Her Customers
Present the following problem to students:
A veterinarian must take the weight of an animal during its medical examination. Using a digital scale, she obtains the following weights:
Dog - 25.969 696 969 kg
Cat - \(4.\dot{5}\) kg
Rabbit - 1.296 7 kg
She needs to round up to the nearest unit so that she can report the weight to her clients. What will be the weight of each animal rounded to the nearest unit?
Allow students to use the strategy of their choice to solve the problem.
Example
Dog
The weight of the dog, rounded to the nearest unit, is 26 kg.
Cat
The weight of the cat, rounded to the nearest unit, is 5 kg.
Rabbit
The weight of the rabbit, rounded to the nearest unit, is 1 kg.