Mathematics 5 curriculum guide 2015 I table of contents acknowledgements

Achievement Indicators:

---

61
MATHEMATICS 5 CURRICULUM GUIDE 2015
Suggested Assessment Strategies
Resources/Notes
ADDING AND SUBTRACTING DECIMALS
General Outcome: Develop Number Sense
Authorized Resource
Interview
• 
Tell students: We are going to put up a new bulletin board in the 
classroom. The border needed comes in lengths of 113.5 cm. The 
perimeter of (distance around) the board is 406.9 cm. Is it reasonable 
to use six lengths of border? Explain.
(5N2.7)
Journal
• 
Ask students to respond to the following prompts;
(i) Jimmy is going to buy three packages of gum. Each package
of gum costs $1.37. How can he estimate how much money he
will need for his purchase?
(5N2.6)
(ii) Adam was given two Newfoundland puppies for his birthday
named Ebony and Ireland. When they were born, Ebony
had a mass of 0.775 kg and Ireland had a mass 0.836 kg.
Estimate the total mass of Ebony and Ireland and explain your
estimation strategy.
(5N2.6) 
• 
Ask students to estimate each of the following differences:
(i) 685.777 – 217.93 (ii) 685.073 – 274.1
They should explain the strategy used and identify which estimate is 
closer to the actual difference.
(5N2.6)
Paper and Pencil
• 
Ask students to solve this problem:
Judy used the following strategy to estimate the sum of 365 and 437.
Judy’s thinking: I used front-end estimation. 
365 is about 300 and 437 is about 400. 
300 + 400 = 700 
My estimate for the sum of 365 and 437 is about 700. 
Ask students how they could help Judy adjust her estimate
to make it closer to the calculated sum. They should explain
their thinking without doing the actual calculation.
(5N2.6)
Math Focus 5
Lesson 3: Estimating Decimal 
Sums and Differences
TR: pp. 22-25 
SB: pp. 88-91
Note
Lesson 4 is optional, as there is no 
direct mention of mental math 
in the outcomes; however it may 
be interesting and useful for some 
students.

---