Mathematics 5 curriculum guide 2015 I table of contents acknowledgements

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MATHEMATICS 5 CURRICULUM GUIDE 2015
Specific Outcomes
ADDING AND SUBTRACTING DECIMALS
Suggestions for Teaching and Learning
Students will be expected to:
Number
As students learn to add and subtract decimal numbers, they should 
connect with what they learned about adding and subtracting whole 
numbers. In Grade 4, students have added and subtracted tenths and 
hundredths. In Grade 5, they will expand this to work with thousandths. 
It is recommended that students revisit adding and subtracting to 
hundredths before moving forward to examples involving thousandths. 
Achievement Indicator:
5N2.8 Describe contexts in which 
overestimating is important.
Brainstorm with students to create a list of real life situations in which 
overestimating is important. When determining if you have enough money 
for a particular purchase, for example, it may be advisable to overestimate 
the total of the goods to be purchased to ensure you have enough money.
Ella is at the grocery store with only $20. She needs to buy milk $3.98, 
bread $2.29, eggs $2.76 and a steak for $8.67. When she gets to the cash 
register, will she have enough money to buy everything she has selected? 
Overestimating is also important in planning a birthday party or similar 
event to ensure there is enough food for all guests and to accommodate 
any unexpected people who attend the party.
5N2 Continued...

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MATHEMATICS 5 CURRICULUM GUIDE 2015
Suggested Assessment Strategies
Resources/Notes
ADDING AND SUBTRACTING DECIMALS
General Outcome: Develop Number Sense
Authorized Resource
Math Focus 5
Lesson 3: Estimating Decimal 
Sums and Differences
TR: pp. 22-25 
SB: pp. 88-91
Journal
• Ask students to respond to the following prompts:
(i) Sophie and her sisters, Ruby and Rhonda, are
going to the theatre. They will each need to each purchase
a ticket which costs $7.85, and they would each want
to purchase a snack pack that costs $8.99. Their parents give
them $50. Use estimation to determine if they will have
enough money.
(5N2.8)
(ii) Describe a situation in which you would round $12.35 to $13
instead of down to $12.
(5N2.8)
Paper and Pencil
• There are 310 students going to the Arts and Culture Centre to 
see a musical. Each school bus holds 50 people. Ask students how 
many school buses should be booked. They should explain their 
thinking.
(5N2.8)
• Ask students to solve this problem:
John wishes to buy a new computer game that costs $109.95
including taxes. He has $43.79 in his wallet and $59.98 in his
piggy bank. He estimates his total cash to be over $110, so he
can buy his game. Is his estimate reasonable? Explain.
(5N2.7, 5N2.8)

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