Strategies2012

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Strategies2012

  1. 1. 8+5 =
  2. 2. 9+8 =
  3. 3. I count up to 8 inmy head then counton 9, 10, 11, 12, 13
  4. 4. I get 8 counters and 5 more counters then count them all.
  5. 5. 8 + 2 = 10 so 10 + 3 is 139 + 1 is 10 so 10 + 7 is 17
  6. 6. I count on from the biggest number.So I go 9… 10, 11,12, 13, 14, 15, 16, 17, 18
  7. 7. 8 + 8 is 16 then add 1 OR9 + 9 is 18 then takeaway 1
  8. 8. There are 36 people on the bus. 9 more people get on the bus. How many people are there altogether on the bus?What strategies would you use to solve this problem?
  9. 9. 36+9 =
  10. 10. If you add 4 onto36 you get 40 thenyou add on theother 5 to get 45people on the bus
  11. 11. I counted onfrom 36 using my fingers and got to 45.
  12. 12. Add on 10 then takeaway 1.When you add on 10 youget 46 then you need to takeaway 1 to get 45.
  13. 13. I know that 6 plus 9 is 15,so 30 + 15 is45.
  14. 14. I know 6 + 6 is 12so 36 + 6 = 42.Then add on the 3more to get 45.
  15. 15. Te Kaha has 47 marbles. He plays Stacey and loses 8 marbles to Stacey. How many marbles is Te Kaha left with?What strategies would you use to solve this problem?
  16. 16. I used balancing. +2 47 – 8 = I compensated: +2 49 – 10 = 39 47 – 10 = 37 37 plus 2 = 39 47 – 8 = If I split 8 into 7 and 1, so I can do 47 – 7, which equals 40, then I only haveI used an open number line! to take away one -1 -7 more, which equals + 39! 39 240 47 0
  17. 17. Number StrategiesThere are 53 people on the bus.29 people get off.How many people are left on thebus?What strategies would you use to solve this problem?
  18. 18. I used place value 53 – 20 = 33. Minus another I used tidy 9. Split the 9 into 3 and 6. numbers: 33 - 3 = 30 so 30 – 6 = 24 53 – 30 = 23 23 plus 1 = 24 I used an open number line! 53 – 29 = +20 +3 I think of +1 + 5329 2 30 50 53 -29 0 3 – 9 I can’t do so I borrow a ten. 13 – 9 = 4. I used balancing. 4 tens – 2 tens = +1 53 – 29 +1 = 20. 54 – 30 = 24 It’s 24.
  19. 19. Number StrategiesThere are 47 children in thehall. 28 more children arrive.How many children are in theschool hall now? What strategies would you use to solve this problem?
  20. 20. Four rows of ten is 40 and two rows of ten is 20, so 40 + 20 = I used tidy 60 with 7 and 8 left! numbers: Double 7 = 14 plus 1 = 15 50 + 28 = 78 so there are 75 children. 78 - 3 = 75. I use an open number line! 47 + 28 = +3 I think of +20 +5 4747 +28 75 7 plus 8 is 15, so that’s 5 and carry one. 4 plus 2 is 6 I know that 50 plus 30 is 80 plus one more ten and 3 plus 2 is 5, is 7. so the so 80 - 5 is 75. answer is 75.
  21. 21. Number Strategies 8+5= 9+8=
  22. 22. Make sense of these strategiesI count up to 8 in my head I get 8 countersthen count on 9, 10, 11, 12, and 5 more13 counters then count them all. 8+5=8 + 2 = 10 so 10 + 3 is 13 9+8= I count on from9 + 1 is 10 so 10 + 7 is 17 the biggest number. So I go 9… 10, 11, 12, 13, 14, 15, 16, 17, 18 8 + 8 is 16 then add 1 OR 9 + 9 is 18 then takeaway 1
  23. 23. Number StrategiesI have $387 in my savings account.I decide to buy a small TV for mybedroom and it costs $193.How much money do I have left? What strategies would you use to solve this problem?
  24. 24. I rounded up to 390 and takeaway 190 to get 200. I used my doubles. then I need to take away Double 190 is 380. the 3 I added on plus the So double 193 is other 3 so its 194. 386 plus 1 more to get 194. “I use an open number line!” 387 - 193 = +100 +87 “I think of +7 + 387193 2 200 300 387 -193 0 7- 3 is 4. 8 – 9 I can’t do so I borrow a hundred. I use balancing. 180 – 90 = 90. -3 387 – 193 = -3 200 – 100 is 100. 384 – 190 = 194 It’s 194.
  25. 25. Number StrategiesI have a 6.3m length of fabric. I used 3.75m to make a coat. How much fabric have I got left? What strategies would you use to solve this problem?
  26. 26. 6.3 – 2.3 = 4 4 – 0.25 = 3.75 What visual so 2.3 + 0.25 = supports could you use to 2.55m support these strategies? “I used an open number line!” +0.25 +2 +0.3 +3.75 2 4 6 6.3 What knowledge do 0 students require to solve problems at this level? 6 6.3 – 3.75 =
  27. 27. Addition and Subtraction StrategiesCounting Counting all Counting on/back ___________________________Part- Using one fact to derive anotherwhole Near-doubles Making tens Using fives Known multiple facts Partitioning Standard place value partitioning Rounding & compensating Through the tens Reversibility Equal additions Commutative Averaging Equivalency

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