Years K - 6
A game for two players using two calculators.
Play with a grown up until you learn the game.
Then you can be the teacher for someone else.
- One calculator each (there's one on your phone)
- A collection of bottle caps or other objects for counting such as pebbles or pasta
- Write the title of this challenge and today's date on a fresh page in your maths journal.
This game is easily adaptable to children with a wide range of abilities and experience.
Learn it first at the easier level of Six Plus then choose more challenging numbers and operations if you need to.
How To Play Six Plus
Player A will hide a number in their calculator. Player B has to find out what it is.
- Players agree on using plus (addition) and pressing the + button.
- Players agree who is going first. The first person is called Player A.
Both players draw like this in their journal to show what has happened.
- Player A shows Player B that they are pressing these buttons:  and [+].
- Secretly Player A presses one more number then presses equals [=].
- Player A puts their calculator down in front of Player B to show the answer on the screen. We will pretend fifteen (15) is on the screen.
6 + = 15
What do you think the box means?
|Player B knows what buttons were pressed to start the game and
knows the answer.
Now they have to guess the secret number.
They keep guessing until they get it correct.
They score one point for each guess.
Guesses are written in the journal like this:
6 + = 15
- Player B presses  and [+] and [guess] and [=].
- If the answer is the same as Player A's screen number, they write the guess and score one (1) point.
- If the answer is not the same as Player A's screen number, they write the guess and score one (1) and start again at Step 1.
- Player B must keep guessing until they get the same as Player A's screen number.
When Player B is correct, swap jobs and play again.
When both players have had the same number of turns to hide the secret number,
the player with the LOWER SCORE WINS.
Why do you think the low score wins?
Do you know a sport where the low score wins?
Changing The Game
|One question a mathematician asks a lot is What happens if ...?
Change the game with this question and give yourselves more and more challenges.
You might ask:
In other words, keep the same way of playing the game, but change the numbers and operations you play with.
- What happens if we play 4 Plus or 9 Plus?
- What happens if we use two digit numbers and plus?
- What happens if we play 20 Minus or 99 Minus?
- What happens if we play 6 times?
- What happens if we use two digit numbers and times?
- What happens if we use decimal numbers?
- What happens if we use negative numbers?
Have fun exploring Six Plus.
We suggest it is used at least three (3) times a week
for about ten (10) minutes
for several weeks.
This pair has changed the game to 9 Times
and are using 2 digit numbers.
Making or Drawing Answers
- Just once each time you play, make a model of what happened by using your screw caps, or do a drawing.
- For example, using 6 + 9 = 15, you might make or draw this.
- Which part is Player A?
- Which part is Player B?
- Which part is the secret number?
- Which part is Player A's screen number?
Investigate all the ways the picture tells you the value of the screen number and report in your journal.
For example, this one shows 15 because:
- 6 + 9 = 15
- 6 + 6 + 3 = 15
- 2 x 6 + 3 = 15
- 2 + 2 + 2 + 2 + 2 + 2 + 3 = 15
- 6 x 2 + 3 = 15
- 3 + 3 + 3 + 3 + 3 = 15
- 5 x 3 = 15
- 18 - 3 = 15
- 2 x 9 - 3 = 15
- ...and there's probably more
Touch and tell to show each other where these equations are in the picture.
Just Before You Finish
Each day you play the game, ask yourself What did I learn about numbers today? and write or draw your answer in your journal.
Answers & Discussion
These notes were originally written for teachers. They have been shared from the Members section of Calculating Changes, which is a division of Mathematics Centre.
Send any comments or photos about this activity and we can start a gallery here.
Maths At Home is a division of Mathematics Centre