Earlier this year we had the pleasure of having Michael Ymer visit our school and show us some brilliant strategies for teaching

maths. I would highly recommend him for those that need to revisit the fun and simplicity of teaching maths. Here are some of his calculator games he shared with us.

Calculator games and activities

While calculators can be used for simply checking written calculations, teachers need to take full advantage of the potential of calculators as a teaching and learning tool.

Below are several calculator activities that provide the opportunity for students to take risks and investigate basic concepts in mathematics.

Using the Constant Function key to enhance number skills [All levels]

Children can work individually with a calculator or take turns with a partner. The constant function key [= button] provides the opportunity for children to practise their counting skills and see patterns appropriate to their developmental level. Let’s say a student would like to count by threes starting from zero. If he/she enters 0+3= and then continues to press the = button the display will go up by threes. Using a 100 number board and a transparent counter to help follow the patterns works well. As students become familiar using the constant function key they may wish to close their eyes and guess the next answer…. guess the next several answers with their eyes closed as they press the constant function key.

Variations

• Change the counting number… try counting by 101, 99, 0.9
• Change the starting number
• Count backwards using the - ’n key and constant function. Young children will need to have access to a 100 number board.

Investigate using the constant function key and all four operations. It’s great to practice doubling, tripling, halving, decimals and negative numbers.

Change it – Place value focus. [All levels]

Partner activity where like ability pairs take it in turn to enter a number into the calculator and change digits. For example, one child creates a number and enters it. Lets say 342. He/she then asks the other child to change a digit. For example, change the 4 into a 7. The partner then needs to + 30 and the number becomes 372. Swap over and the activity continues. The students need to determine the value of the digit that is being changed. Place value materials such as MAB may need to be used to help students see the value of digits in different places. If a mistake is made the game simply continues with the new number.

Variations

• Simplify the activity for young children by using a single digit number and giving each pair ten unifix cubes so that they can make the numbers and then use the calculator to check.

• Vary the range of numbers selected to cater for mixed abilities.
• Take it in turns changing digits to make a set number i.e. 999, 0
• Use subtraction or addition to change a digit.
• Change more than one digit at a time with one move. For example the entered number is 51 478. Change both the digits 1 and the 7 into 6’s with the one move. This can be challenging. Students will need to think along the lines ‘ I will need to add 6 000 and then take away 10. Therefore if I add 5 990 I should get 56 468.
• Use decimals in the activity.

Hit the target – place value and addition focus [All levels]

List several suitable target numbers on the board. For example 5, 10, 20, 50, 100, 1, 101.01 depending on year level.

Children work in like ability pairs selecting an appropriate target number. They take it in turns to enter a number that is smaller than the target number. The challenge is for the other student to enter the matching number to hit the target. For example. Two children agree to play target 20. Player one enters 12 into the calculator. Player two has the challenge of finding and adding the number to make 20. In this case 8. Swap roles after each shot.

Variations

• Use target numbers such as 101, 9.9, 17, - negative numbers.

Make my number– place value and operations focus [All levels]

Tell the children that one of the buttons on your calculator is not working. [You can purchase overhead and individual calculators that have a disabling function key.] Let’s say that the 9 button is not working. The challenge for children is to work out how to display the 9 on the calculator screen using other buttons. If able invite children to write down in order the buttons they used. Ensure that aids such as ten frames boards, counters, unifix, popsticks etc are available for use.

Variations

• Using the above example challenge students to make 90, 109, 99, 9009, 9.99
• More than one button is broken. For example the 7, 8 and 9 button are not working. Work out clever ways to make the numbers 78, 777, 9087.98 etc.
• The 9 button and the + button are not working.
• Invite children to make the number 9 ten different ways. Can they use all four operations in their equations? Challenge students to make an equation to equal 99 that uses two or more operations in the one equation.
• Teachers and students can make up their own broken button challenges.

Guess and Press – Focus on estimation and ordering whole and decimals [Year 3 +]

Children work in pairs or threes. Teacher specifies a starting number [say 23] and a target number [say 100]. Notice that the starting number will not evenly fit into the target number. The aim of the game is to find what number is required to multiply with the starting number to hit the bullseye, which in this case is 100. The children task it in turns guessing what number is required to multiply with the starting number in order to get as close as possible to the target number. After five turns each, the closest to the target is the winner. Select another set of numbers and play again.

Sample play Starting number Guess Answer

Jessica 23 x 6 138

Simon 23 x 4 92

Jessica 23 x 5 115

Simon 23 x 4.5 103.5

Jessica 23 x 4.4 101.2

Simon 23 x 4.3 98.9

Etc

Consecutive Number hunt – Focus on estimation and place value. [Years 4 +]

Teacher privately multiplies two consecutive numbers together and notes the answer. The answer is then written on the board and students are invited to find the two consecutive numbers that equal that number when they are multiplied together. Students will need to use the strategy of guess, check and refine in this task. The teacher will need to list several different answers for fast finishes.

Variations

• List the answer to three consecutive numbers either added or multiplied together.
• List the answer to two consecutive [tenths] mixed numbers multiplied together. For example list 28.62 on board. Children search until they narrow it down to 5.4 x 5.3.

Calculator 21- [Focus is counting on and using strategies to predict [All levels]

One calculator between two.

Using only the numbers 1, 2, and 3 children take turns adding one of these numbers until someone hits 21. The person who hits 21 wins the game.

Variations

• Play to 31
• Play to 100 using numbers 5, 6, 7, 8 or 9.
• Begin with 100 take away 5, 6, 7, 8 or 9 and first to hit a negative number loses.

Sharon, This next section is necessary for teachers to read. Not sure how it can be included.

Resourcing and management

No matter how good a calculator activity may be, it is unlikely to reach its expectations if effective management of calculator use has not been considered in the planning of the lesson. Below is a list of suggestions that might help teachers.

• Invest in buying a couple of overhead calculators for your school. Trying to demonstrate a calculator activity using a normal calculator is extremely difficult. Ever tried holding up a calculator and discussing buttons to press with young children sitting on the floor. Once you have used an overhead calculator in your teaching you will wonder how you ever coped without one. If your room doesn’t have a screen, use the blinds, whiteboard or simply the wall or chalkboard to project your calculator.

• Consider having students [particularly young students] working at their tables not the floor.

• Declutter tables. Clear the jumbo pencil case, drink bottle, library books etc from the table. It makes a big difference to have only a calculator and maths book in front of a student, particularly for those students who find it difficult to concentrate on tasks. It is most effective for a teacher to be at the front of the classroom using the overhead calculator to demonstrate an activity and then for the children to focus immediately on the calculator in front of them.

• During partner activities consider having the rule that the calculator must not be picked up at all by either student. It needs to be placed on the table between both students. This helps eliminates the possibility of one student dominating the calculator while the other student loses interest because they cannot see the calculator.

• Classrooms need to have at least one calculator between two students. As children get older [Years 4 on] it is ideal for children to have their own calculator.

In partner activities emphasise that each student has the responsibility to teach rather than tell their partner how they work out answers.

Conclusion

Calculators are wonderful tools for children to investigate, discover and use to help make sense of number concepts. While young school beginners are motivated by natural curiosity, low attaining students are provided with an opportunity to think about mathematical relationships and take risks without the burden of written computation. Our high attaining maths students can take the computation short cuts in order to solve complex problems that require higher order thinking skills.