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
Students should make the transition from concrete and pictorial 
representations to the symbolic. They should continue to align place 
values, regrouping when necessary. 
Students should apply addition and subtraction strategies for whole 
numbers to their work with decimal numbers.
The renaming method, which was introduced in Grade 4, may also 
be used with decimal numbers. This strategy is particularly useful 
when working with a top number (minuend) which ends in zeros.
Using renaming creates numbers which are much easier to work with 
because there is no need for trading or regrouping. When determining
10 - 6.789, for example, 10 changes to 9.999 to avoid trading and then 
0.001 is added to the answer once it is acquired. Students may need to 
review that 10 = 10.000 (e.g., equivalent decimals).
A common error occurs when students forget to add on the extra 0.001.
Another renaming method to consider for subtracting 10.000 – 6.789 
is to simply decrease both numbers by 0.001 to produce 9.999 – 6.788.
This way the answer requires no adjustment. 
5N11 Continued...
5N11.4 (Continued) Solve a 
given problem that involves 
addition and subtraction of 
decimals, limited to thousandths.
Achievement Indicator:
7.621 
- 4.317 
3.303 
1 10 
10.000 (subtract 0.001) 
9.999 + 0.001 
- 6.789
-6.789
3.210 + 0.001 = 3.211 
10.000 (subtract 0.001) 
9.999
- 6.789 (subtract 0.001)
-6.788
3.211 

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