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February 2013 Coaches Meeting. Strategies for Whole Number Computation. Three Types of Computational Strategies. Direct Modeling- Problem Types. Identify the problem type. Match the problem with the problem type. Mental Strategies. Addition and subtraction strategies. Adding On 136 + 143
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February 2013 Coaches Meeting Strategies for Whole Number Computation
Identify the problem type Match the problem with the problem type.
Addition and subtraction strategies • Adding On 136 + 143 136 +100 = 236 236 + 40 = 276 276 + 3= 279 136 + 143= 279 • Partial Subtraction 387- 146 387 - 100= 287 287 – 40 = 247 247 – 6 = 241 387 – 146 = 241
Addition and Subtraction Strategies • Compensation 236 + 297 236 + 300 = 536 Subtract 3 536 – 3 = 533 236 + 297 = 533 Adding more than is required , and then subtracting the extra amount. • Compensation 547-296 547 – 300 = 247 Add 4 247 + 4 = 251 547 – 296 = 251 Subtracting more thn is required, then adding back the extra amout
Addition and Subtraction Strategies • Moving 153 + 598 Move 2 from 153 to 598 151 + 600 = 751 153 + 598 = 751 • Constant Difference 146 – 38 Add 2 to both numbers to create expression with friendly numbers 148 – 40 = 108 146 – 38 = 108
Use and explain your Strategy Yesterday there were 57 penguins sitting on the iceberg. Later 34 penguins joined them. How many penguins are now on the iceberg? There were 72 penguins sitting on the iceberg. 49 penguins jumped into the icy water. How many penguins are still on the iceberg?
Perfect 500 Number of Players: 2 or 3 Materials: One deck of 40 cards (4 each of the numbers 0-9) Directions: The goal of the game is to have a sum as close to but not over 500 at the end of five rounds. To begin, shuffle the deck of cards. Deal 5 cards to each player. Use four of the cards to make 2, two-digit numbers, saving the fifth card for the next round. Try to get as close as possible to 100. Record your addition problem and sum on the recording sheet, keeping a running total as you play. For the second round, each player gets four cards to which they add the unused card from the first round. After five rounds, the winner is the player who is closest to 500 without going over.
Representations:Models for Thinking Strengthening the ability to move between and among representations improves the growth of children’s conceptual understanding. Vandewalle, J. Elementary and Middle School Mathematics Teaching Developmentally. Pearson Education, 2007. . pictures manipulative models oral language written symbols Real-world situations
Models for thinking A model for thinking about a mathematical concept refers to any object, picture, or drawing that represents the concept. • To see a concept in a model you must have some relationship in your mind to impose on the model. • Models give children something to think about, explore with, talk about, and reason with.
Open Number Line Addition (2 digit + 2 digit) A sunflower is 47 cm tall. It grows another 25cm. How tall is it?
Open Number Line Subtraction (2 digit – 2 digit) I need 72 dollars to buy a skateboard. I have 39 dollars already. How many more dollars do I need to save?
