Game – Prime Number Recognition

You will need:

2 dice and a pen and paper.

Take in turns to:

  • Throw the dice
  • From the dice, construct 2 or perhaps 3 numbers. For example, if you throw a two and a three, you can make 5, 23 and 32 (3+2=5, two followed by three is 23 and three followed by two is 32)
  • Score one point for each prime number you have made (so this example scores one for the 5 and one for the 23, scoring two points in total).
  • If you need to use a calculator, then a Casio fx-83GT PLUS can tell you whether a number is prime. This is *not* cheating – students will soon start to recognise the primes they need, rather than having to check using the calculator!

The Winner Is:

The person who has the most points.

Things to discuss:

  • Why are two even numbers always such bad news? (even+even=even and the only even prime number is two)
  • Is it possible to score three points with one throw?
  • If there is a six in your throw, what happens?

This sample space diagram may help:

Sample Space Diagram for 2 Dice




















































Cancelling Fractions. A game for 2-4 players.


You will need:

Slow Rounds:

  • Play like this while they get used to the game.
  • Give out a card, read the fraction, ask them if they have it on their board? (Probably they will say no)
  • Ask which table both those numbers are found in? For example, if the card says 15/20, those two numbers are both in the 5 times table. Ask what position the 15 is in (answer, 3). What position is the 20 in (answer, 4). So, 15/20 is WORTH 3/4.
  • The pupil covers 3/4 with the card.
  • Take in turns until someone has 4 covered (or all covered, depending what pace you want).

Fast Rounds:

  • Play like this once they are really confident and getting bored with the pace…
  • Hand out one card each, fast, they grab it and place it on their board. Commiserate if it is a duplicate that they don’t need “Oh no, not another one EQUIVALENT to 3/4!”. If they are pleased, celebrate “Great, you needed 2/9”. This gets the correct terminology bedded in, and also they see that fractions that are equivalent to each other generally LOOK really different.
  • If 2 pupils draw (covering 4 fractions) have a tie break round with another card. At this pace, it works well to aim to cover all the factions up.
  • If someone goes “bingo” check their board to make sure all the cards are in the right place.

Super Fast Round:

  • Give each pupil 5 cards and see if anyone can go bingo.

Bonus level thinking:

  • “You need one more card. What do you want to get?” Suppose it is 2/5. Point out they need a fraction made up of a “position 2, position 5” pair. Placing one finger in each position explains this nicely. It’s very gratifying if they get what they want straight away!
  • Get the pupils to highlight the odd numbers before they start. Think about whether a fraction’s numbers are odd or even, or one of each, and which tables they should be looking in. Being hazy about the importance of odds and evens is common amongst struggling mathematicians.