# Flip Flop - matching cards

The aim of this game is to match pairs of cards.

Click on a card in the interactivity below to turn it over. Then click on another one. If the two cards match, they will stay face-up. If the two cards do not match, they will return to being face-down.

The game ends when all the cards have been matched in pairs.

How do you know when a card matches another card?

Can you remember where particular cards are to help you match the pairs?

We would love to hear about the strategies you use as you play the game.

You may like to explore these alternative versions of the interactivity:

- Play with a scoring system - you start with 100 points, lose 10 points whenever you turn over cards that don't match, and add 50 points whenever they do match.
- Play against the clock - can you beat your personal best?
- Play with face-up cards - the cards are all face-up at the start so you can focus on the maths rather than the memory aspect of the game.

Here is a PDF version of the game, which you can print off to play away from the computer if you wish. If you print double-sided, the cards will each have an NRICH logo on the back. If you would prefer them to be blank on the back, please just print the first page.

We had many solutions come in from the Bristish Vietnamese International School after one of our NRICH team led some PD there. The following pupils sent in their thoughts, ideas and pictures of their results:

Khoa, Mai Khanh, Teppi, Nguyen Hoang Nam, Annie, Tuong Anh, Nguyá»…n, Phan Ngoc Thao Nhi, Huy Nam, Jonny, Mai, Hoang ha nguyen khanh, Quang Ha Nguon Khanh, Le Hoang Anh, Nguyen Minh Thanh An, Duc Thinh, Simon, Olivia, Michelle, Andy, Henry, Khang and Trá»‹nh.

Here are some of their observations:

My solution is if you found the first solution but it doesn't work out, the answer to the first solution may link to the next solution, so keep on looking for answer.

First I will choose two random squares if they do not match I will remember the number or the calculation, and also remember where they are. Next I will choose another random square. If it matches with one of the squares that I already chose then we already have a pair. But if they don't match just keep remembering the number or the calculation. Don't forget to remember where they are.

The method is trying to memorize the number or thinking fast math because this way will help you do questions more quickly. But if you want to do this you have to practise this frequently.

To solve the matching game with a faster time, you need to remember the place of the numbers and the addition or subtraction. The reason to do that is because there are a lot of numbers and calculations so we need to remember what number is correct for that calculation. For example, first time, you choose 12 and 11+3. Next time, you choose 14 and 7+5. So if you can remember the places of 12 and 11+3, you can make it 7+5 and 12, 11+3=14.

To be fast you must have somewhat of a good memory. You must remember where the equations are. First, calculate the equation and remember its position and answer so when you find the answer it will be easier. You can do the same to an answer, think of an equation that will most likely be in the game. If that doesn't work try to remember an equation that can make this answer. On my many game times, I discovered that most of the simple equations like 1+1+3 are most likely to pop up in the middle. You should explore the middle part first.

Here are some of the completed views they achieved:

Thanks all of you from the Bristish Vietnamese International School, well done!

We had the following submission from the International School of Brussels:

Jeshan from Prince Edward Primary School wrote:

I chose numbers which add up to the number hidden on the card and then I solved four cards. I really enjoyed doing the whole game.

Thank you all for these submissions and comments.

### Why play this game?

This game offers children a motivating context in which to practise mental addition and subtraction. It also encourages recognition of number bonds and will help develop an understanding of equivalence.

### Possible approach

Begin by introducing the class to the printable cards before the interactivity. Give out sets of cards to each pair of learners and encourage them to lay them all out, face-up. You could offer any of the following prompts to encourage them to engage with the representations on the cards:

- How might you group/sort the cards?
- How might you order the cards?
- What is the same about the cards? What is different?
- Take three or four cards. Which one doesn't belong? Why? Can you choose a different card which doesn't belong? Why?
- Create another pair for the set. Can you create a pair which you think would be relatively easy to match? Can you create a pair which is harder to match? How did you decide which was easy and which was difficult.
- Rather than giving out all the cards, you could just give out half the set of cards so that each card does not have a pair. Invite learners to create a pair for each card they have been given.
- Share the cards out in a group of four. Take it in turns to describe what is on one of your cards
*without showing it to anyone else*. Who has a card which shows an equivalent amount?

Once learners have explored the cards in some of these ways, show them the interactivity. You may like to begin to play the game on the interactive whiteboard with the whole group. You could choose a card and, before turning over a second card, invite learners to talk in pairs about what might match. As more cards are revealed, trying to remember which cards have already been seen and what they have on them becomes important too.

As soon as the class has a flavour of the game, suggest that they work in pairs at a computer, laptop or tablet. (They could use the printable cards if this is not feasible.) As they play in pairs, watch and listen, and make a note of anything you overhear that you'd like to refer to during a mini plenary. It may be that you notice a misconception more than once, or that you'd like to spend a
few minutes inviting learners to explain *how* they knew that two particular cards are a match.

You could return to the interactivity in subsequent lessons, perhaps as a starter or during a plenary, where appropriate.

### Key questions

What might the matching pair for that card have on it?

How do you know those two cards match?

Have we already seen a card that might be a match for that one?

### Possible support

Playing the game with all the cards face-up is a great way to focus on the mathematics if the memory aspect proves tricky for some children. You can do this in this version of the interactivity.

### Possible extension

Some pairs may enjoy challenging themselves to get as many points as possible using this version of the interactive game and/or trying to complete the game as quickly as possible (this version of the interactivity has a timer). Some of the suggestions in the opening paragraph of the 'Possible approach' above would make good extension tasks.