Simple Calculator Activities - Geocities.ws

Simple CalculatorActivitiesThese activities were developed with BRAC primary schools in mind but couldbe the basis for activities in any classroom where there is only one calculator.Each school will have one simple strong solar powered calculator and a set ofactivity sheets either in booklet form or printed on separate sheets.About the MaterialsThe calculator activities are designed to: Help children learn on their own how to use the calculator starting with thefour basic operations Encourage problem solving skills Encourage children to talk about how to do mathematical problems ingroups Help them use the calculator to check answers Help them use the calculator to improve their mental mathematics andskills of estimation, prediction and approximation Learn more about number patterns Learn more about large numbers by using the calculator Learn more about decimals by using the calculator Learn about the connection between decimals and fractions using thecalculator Introduce decimal notation and negative numbers for handling largenumbers which often fascinate children Practice reading Allow children to work without the direct interference of the teacher

CONTENTCollection AA1A1A2A3A3A3A3A4Playing with the calculatorLearning to Add on the calculatorTake Away - Place ValueAdd up - Place ValueTarget Addition 1Target Addition 2Make 99Missing SignsSimple introductionIntroduction to Activity to help understanding of place valueDeveloping place valueUsing calculator to practice mental additionUsing calculator to practice mental additionMental addition practiceProblem solving using operationsCollection BB1B1B2B2B2B2B3B4B4Checking with the calculatorGetting to Know Your CalculatorDivide by 10Fractions on the CalculatorGuessing GameMultiplication PuzzleMultiplication ChallengeOdd and EvenQuick Mental AdditionUsing division to check multiplicationFractions to DecimalsMental skills of division by 10Equivalent fractionsEstimating MultiplicationMental estimationFinding missing figures, estimation, deductionResult of multiplying - odd / evenEstimation, rounding off to get answers mentallyCollection CC1 The Magic of 101C1 Fraction FunC2 Multiplication with DecimalsC2 Multiplying DecimalsC2 Mystery MultiplicationC2 Some Strange DivisionsC3 Magic AddingC3 Mystery Problems with BracketsMultiplication patterns, deductionUsing the calculator to compare fractionsEquivalent multiplicationsEstimation and counting decimal placesProblem solving involving estimation/deductionRecurrent DecimalsSimple programming on the calculatorEstimation, deductionCollection DD1 Patterns in NumbersD2 Upside-down calculator word gameD3 Magical Birthday Math TrickBeauty in MathematicsWords in numbersCalculates birthday magicallyReferences:Calculator games. Retrieved 2 April 2008 from tor-games.htmlCalculator pattern puzzles. Retrieved 20 Mac 2008 from tivities%20Index.htm.

A1 Learning to add on the CalculatorPritti is learning to add on the calculator. She wants to add 36and 57First she checks that the calculator is clear. She presses C andthe calculator shows 0Next she presses 3 then 6. The calculator shows 36Next she presses . The calculator still shows 36Next she presses 5 and 7. The calculator shows 57Next she presses The calculator shows 93Can you think what the calculator has done!Now let everybody in your group try and do one of these each27 67 45 28 36 39 58 89 67 89 Use your calculator to find out which of these sums has been addedcorrectly78 4512365 7613134 87121123 1242474556 867913225Can you find out how to do these on the calculator?123 34 453 78 34 56 434 893 545

A1 Playing with the CalculatorHere is your calculator.This is the displayThese are the keysThis is the on/off keyThis is the clear keyYou can discover for yourself how it works.Can you find how to turn it on.?What do you see when the calculator is on?Now discover how to turn it offTurn it on again.Put 123 into the calculator by pressingIt is very important to know how to clear the calculator. Before you starteach calculation press C and make sure 0 is showing.Let everyone in the group practice putting in a number and clearing it.Now try some simple calculations.Can you do 12 35 ? Pressing 12 35 is not enough. There is a veryimportant key that you must press at the end. You must press after 12 35 to make the calculator work out the answer.Let everybody try an addition. One person make up the sum and anotherworks out the answer on the calculator. Make sure you check the answer.It is easy to hit the wrong key by mistake.Now try subtraction.145 – 56Remember to press at the end. Let every body try asubtraction.Now discover how to do multiplication27 x 35Now try divisionFirst try 144 divided by 48 Does it work? Now try these 150 divided by25, 756 divided by 21, 5460 divided by 35

A2 Take AwayPlace ValuePut this number on the calculatorWhat will happen when you pressLet everyone guess the answer.Then pressWere you right?What will happen when you pressAll guess then press and seeWhat will happen when you pressAll guess and then press and see.What will happen when you pressAll guess and then see.Now you are ready for a game.4753

A Group GameTake awayPlace ValueThe group sit in a ring. The first player puts in any 5 figure number eg45389She shows it to the whole group and they all say the number.Then she passes the calculator to the next in the group. Now the challengeis to make the last figure, 9, change to a 0 so that 45389 becomes 45380She should say aloud what she will doI will press – then 9 and The calculator will now show 45380All the group check to see if the new number has a zero in itNow the calculator is passed to the next person. She must make anotherzero appear so that there is 00 at the end of the numberI will press – and 80 and .This will give 45300Everybody checks that she is correct.The next player must make 000 at the end of the number.The next player must make 0000 at the end of the number.Keep passing the calculator until the number is zeroNow a new player sets a new number and the game continues. Make sureevery one in the group has a turn at setting the number.Variationsa) have a bigger number with 6 digitsb) or play so that the children choose which figure should goeg 37865 is set. First player chooses which figure is to disappear.Make the 7 vanish and become 0so the next person has to make the 7 disappear and 0 come in its placeeg she must press – 7000 to give 30865. If she is correct she passesthe calculator to the next person and chooses which figure is to go nexteg Make the 6 turn to 0.The next player has to make the 6 disappear, by pressing – 60 Continue until just zero is on the calculator

A3Add UpPlace ValueSet 56471 on the calculatorWhat will happen when you pressCan you work out the answer before you press the keys?Now press and see if you were right.What will happen when you pressDo you all agree?Now press and see if you were right.What will happen when you pressDo you all agree?Now press and see if you were rightWhat will happen when you pressDo you all agree?Now press and see if you were right.Now go on to play the Add Up game

A Group GameAdd UpPlace ValueAim of the gameEach player tries to make a new O appear by adding.The first player sets any 5figure numberExampleThe first player sets85634 on the calculator.The calculator is passed to thenext player. She must makea 0 come at the end of thenumberExampleThe next player presses and 6 and The calculator will show 85640Pass the calculator to the nextperson. She must make another0 appear so the number ends 00ExampleThe next player presses and 60 and The calculator shows 85700Pass the calculator to the nextperson. She must make thenumber end 000The calculator is passed to thenext person. She must make0000 at the end of the numberExampleThe next player presses and 300 and The calculator shows 86000ExampleThe next player presses and 4000 and The calculator shows 90000Now choose another number to start with. Play the game again.Let everyone have a turn at setting the first number.Can you change the rules of the game to make a new game?Perhaps you could start with a six figure number.Perhaps you could try and make 9’s appear instead of 0.

A3Make 99Mental AdditionNeena and. her friends are playing the “Make 99 Game” on thecalculatorNeena puts 43 on the calculator. She passes it to Hamid and says“Make 99”Hamid takes the calculator. He thinks what number to add. Whatnumber do you think he will press? He decides to press 56 Now the calculator shows 99. He was right!Now Hamid clears the calculator and enters 27.Hamid passes the calculator to Nashid and says“Add a number to make 99”Nashid presses 62 and now the calculator shows 89. She waswrong!What should Nashid have entered?Now play this game with your calculator.The Rules of “Make 99”One person in the group sets a number less than 50 on thecalculator. He shows everyone the number and passes thecalculator to another child and says “Make 99”. She has to add anumber so that the calculator shows 99.Other similar gamesHave a different target number. For example play the game“Make 100” or “Make 999”Play a subtraction game. One player sets a three figure numbergreater than 100. The other player has to take away to make thecalculator show 100.Neena set 346 on the calculator. She passed it to Hamid andsaid “Make it into 100 by a subtraction”Hamid pressed – 246 The calculator shows 100

A3 Target Addition - 11232454824667141593211450Pankash is the group leader. He has thecalculator . He chose two numbers from the boxand secretly adds them. Then he shows theanswer to the group. The calculator shows 109.Pankash says, “Which two numbers did I add?”Meetu calls out, “59 50.”Pankash says, “Well done” and passes thecalculator on to a new leader.Now play this game in your group.Here are the rulesThe Rules of TargetAll the group look at the numbers in the box. One personchooses a pair to add on the calculator. She does not let theothers see what she is doing. She shows them the answer on thecalculator and asks “Which numbers did I add?” The first toanswer correctly is the winner. Then the calculator is passed tothe next person in the group who makes up a sum and so on.

A3 Target Addition – 2More boxes to use with Target addition. Always chose the two numbersfrom the same box2630171410204182135433207161010050201115214280

A4Missing SignsSalima and Neena are looking at this puzzle.27 5 63 198Salima says “I wonder what goes in the ?”Salima tries 27 5 63 using the calculator.This gives 95Then Neena tries 27 x 5 63 on the calculator.Do you think this is right. Try it on the calculator.Now try these together with your friends and use thecalculator to check who is correct.24 16 7 389713 25 23 747556 64 75 19523 8 18 20212 20 10 240045 30 17 58

B1 Getting to know your calculatorSome interesting decimalsNeena knows how to find fractions on the calculator.She changes them to decimals!“ Neena, please can you tell us how to change 1/9 intoa decimal on the calculator?”Neena says1/9 is a fraction.To find it on thecalculator wemust change it toa decimalWhat do you find when you do this?Write on your slate1/9 2/9Now use Neena’s method to change thesefractions to decimals.Copy the answers on your slate.3/94/95/9Can you guess what 6/9 will be. Talk with your group and writedown your guess and then use the calculator to find out if youwere correct.Now try and guess what all these will be.Then check on the calculator and 3 if you were right.6/97/98/99/9 oops!!