Strategies for Whole Number Computation

Strategies for Whole Number ComputationFebruary 2013 Coaches MeetingThree Types of Computational StrategiesDirect Modeling- Problem Types

Identify the problem typeMatch the problem with the problem type. Mental Strategies

Addition and subtraction strategiesAdding On136 + 143

136 +100 = 236236 + 40 = 276276 + 3= 279

136 + 143= 279Partial Subtraction387- 146

387 - 100= 287287 40 = 247247 6 = 241

387 146 = 241

Addition and Subtraction StrategiesCompensation236 + 297

236 + 300 = 536Subtract 3536 3 = 533

236 + 297 = 533

Adding more than is required , and then subtracting the extra amount.

Compensation547-296

547 300 = 247Add 4247 + 4 = 251

547 296 = 251

Subtracting more thn is required, then adding back the extra amout

Addition and Subtraction StrategiesMoving153 + 598

Move 2 from 153 to 598151 + 600 = 751

153 + 598 = 751Constant Difference146 38

Add 2 to both numbers to create expression with friendly numbers148 40 = 108

146 38 = 108Use and explain your StrategyYesterday 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 500Number 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 ThinkingStrengthening the ability to move between and among representations improves the growth of childrens conceptual understanding.

Vandewalle, J. Elementary and Middle School Mathematics Teaching Developmentally. Pearson Education, 2007..

picturesmanipulativemodels Real-worldsituationswrittensymbols oral language11Models for thinkingA 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.

12Open Number LineAddition (2 digit + 2 digit)A sunflower is 47 cm tall. It grows another 25cm. How tall is it?

Open Number LineSubtraction (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?

1000 - 647

1000-647

1000-647