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February 26, 2009 Can you do Division? Divide a loaf by a knife - what's the answer to that? ~Lewis Carroll, Through the Looking Glass.

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Presentation on theme: "February 26, 2009 Can you do Division? Divide a loaf by a knife - what's the answer to that? ~Lewis Carroll, Through the Looking Glass."— Presentation transcript:

1 February 26, 2009 Can you do Division? Divide a loaf by a knife - what's the answer to that? ~Lewis Carroll, Through the Looking Glass

2 February 26, 2009 Section 3.4 – division Exploration 3.15 Videos Homework

3 February 26, 2009 Test 2 – Thursday, 3/12 (50 min.) Covers: Text 3.3 & 3.4 (Multiplication and Division) Explorations (so far, 3.13 and 3.15) Class Notes

4 3.4 – Understanding Division Explain what is wrong, and why it’s wrong: “50 ÷ 7 is the same as 50 ÷ 10, which is 5. But, I added 3 to the divisor, so now I need to subtract 3: 5 – 3 = 2.”

5 3.4 (cont’d) Multiplication and Division In mathematics, we say that addition and subtraction are inverse operations. This is why there are related facts: 3 + 4 = 7; 7 – 4 = 3; 7 – 3 = 4 In this same way, multiplication and division are inverse operations: 3 4 = 12; 12 ÷ 4 = 3; 12 ÷ 3 = 4

6 3.4 (cont’d) Exploration 3.15 On your own, make up a story problem for: 15 ÷ 3 As a group: Share your problems. Sort into two or more piles. Select one from each pile and write it on the chart paper.

7 3.4 (cont’d) Vocabulary: In any division problem, dividend ÷ divisor = quotient In word problems, we usually have a rate as part of the problem (e.g. apples per person). Where the rate appears determines the type of word problem.

8 3.4 (cont’d) Where is the rate? 1.Jack has 18 books. If he stacks 3 books per pile, how many piles of books can he make? This is repeated subtraction. 2.Jack has 18 books. If he wants to make 3 stacks of books, how many books will be in each stack? This is partitioning.

9 3.4 (cont’d) Turn to Class Notes pg 11. Take notes that will help you remember each child’s strategy.

10 3.4 (cont’d) With your table, discuss questions 5 – 8 on pg 13. (Cross out the sentence about “Shannon” in #6). When finished, move on to pages 14 and 15. These will be collected on Tuesday.

11 Homework Due Tuesday, 3/3: Link to online homework list


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