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Published byLoren Cross Modified over 9 years ago
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Mastering Whole Number Operations
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Addition and Multiplication involves all single digit addends and factors Addend plus addend equals sum Factor times factor equals product How many basic facts are there????
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100!!!! For each addition and multiplication How???
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1. Understand the meaning of the operations 2. Use thinking Strategies to Retrieve Facts *use facts that they know to figure out facts that they don’t i.e. 2+2 =4 so 2+3 must be one more than that * other stategies include counting on, counting back, skip counting, one more, one less…
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3. Using Consolidating Activities for Drill and Practice games, activities, worksheets all help children memorize these facts
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Counting on … 6+3 start from the 6 and count on three times seven, eight, nine Remind children to start from the larger # regardless of order of the problem..3+6 still starting at 6 and add on three more This method works well for both addition and subtraction Sometimes a calendar works as a good visual to use this method—see next slide
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January 2012 SundayMondayTuesdayWednesdayThursdayFridaySaturday 1 New Year’s Day 234567 891011121314 1516 Martin Luther King Day 1718192021 22232425262728 2930 31
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Use counters 1. Show two groups of 6 2. “How much is 6+6?” 3. Add one more to one of the groups 4. Now we have 6 + 7. “How many altogether?” 5. One more than twelve 6. Count out 13 objects with students 7. 6+6 = 12 then 6 + 7 = 13
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One addend is increased while the other addend is decreased by trying to make one addend 10 Use counters to model two piles 8 + 4=? Manipulate counters so one pile has 10 Now solve
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Order doesn’t matter 3+5 = 5+3 35 = 53 However this does not work for Subtraction and Division 6-4 ≠ 4-6 24/6 ≠6/24
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4 7 17 37 33 13 53 59 89
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John’s calculator is broken. The number 4 key will not work. How may possible combinations can you come up with on the screen to get 4 without actually using 4? John has a math problem for hw and he is still trying to use the same calculator to solve this problem 24-4= ? Can you help him rewrite this problem so he can use his calculator?
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