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Monday, July 8, 2013

Addition & Subtraction

L.I - I have learnt to use Place Value to solve both  Addition & Subtraction Problems.



1.
There are 21 people at a beach, and 13 more people arrive.
Show how to work out how many people are at the beach altogether
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21 + 13 = ___
20 + 10 = 30
1 + 3 = 4
30 + 4 = 34    ☺
Answer - 34      YES!    What strategy did you use?
Respond - I used place value to solve all 3 addition problems.

2
Two classes go on camp together. One class has 47 students and the other has 38.
Show how to work out how many students go on camp
******
47 + 38 = ____
40 + 30 = 70
7 + the 3 from the 8 = 10
10 + the remaining 5 from the 8 = 15      
70 + 15 = 85                 ☺
Answer - 85 - Great to see you set out work neatly.  
Next Step: Try and use another strategy.






3.   A farmer has 63 cows. He buys 39 more cows.
Show how to work out how many cows he has altogether.
******
63 + 39 = ______
60 + 30 = 90
9 + the 1 from 3 = 10
10 + the remaining 2 from the 3 = 12
90 + 12 = 102
Answer - 102  -  
Great use of Place Value as a strategy.

Next Step:  To use another strategy such as Tidy Number or Near Ten.  Post your work and label PORTFOLIO 2013


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