CLASSROOM SESSION A2 Whole Numbers Addition & Subtraction

DRILL & PRACTICE AND

PROBLEM SOLVING CAN HAPPEN SIMULTANEOUSLY

Slides are available at www.banhar.blogspot.com

and Marshall Cavendish Institute’s Facebook

Worchester State University, USAAfter participants were able togenerate possible arrangements,they observed various patternsincluding the fact that the totals areconsecutive whole numbers.

An extension task was assigned. Participants wereasked if the total could ever be 99 and if so, usingwhat set of numbers and what number will be inthe middle square.

Worchester State University, USA

Worchester State University, USA

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Worchester State University, USA

The class got the lowestpossible sum as 356 andthe highest possiblesum as 981.

Can you find sumswhich are lower /higher than those?

Or can you reason thatthose are the lowest /highest possible sum?

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Make numbers so thatthe total is as close to 20as possible.

The winner is the onewho can make numbersthat add up to a totalclosest to 20.

Pick any 3 digits.Make a 3-digit number.Make a different 3-digit number.

Find the difference.Write the difference down.

Circle one of the digits in the difference.Add up the rest of the digits.

Tell me the sum and I will tell you the digit you circled.

Pick any number less than 20.Take turns to subtract 1, 2 or 3 until it becomes zero.This is a game for 2 persons.

The one who get to zero is the winner.

p r o b l e m s o l v i n g

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Procedural fluency is not sacrificed.