Traffic Lights

The game uses a 3x3 square board. 2 players take turns to play, either placing a red on an empty square, or changing a red to orange, or orange to green. The player who forms 3 of 1 colour in a line wins.

Sumo

Reasoning based on this Japanese activity.

Line of Four

A game somewhat similar to 'noughts and crosses' on a much larger space.

Square it for Two

Stage: 1 and 2 Challenge Level:
Here’s a game to play with a grown-up!

How do you play?
You'll need a grown-up to play with.
You'll also need a set of blank grids, or you could use the tablet-friendly Square-it interactivity.

Choose a different colour for you and the grown-up, and take it in turns to draw a dot on the grid. The winner is the first to have four dots that can be joined by straight lines to form a square. Squares can be any size and can be tilted.

Can you work out a strategy? Justify why you think each move is a good one.
How do you know when you've made a square?
Notes for grown-ups
This game offers an excellent opportunity to practise visualising squares and angles on grids and also encourages children to look at strategies using systematic approaches.

Easier version: start by drawing examples of different squares on the grid, and discuss wrong or omitted solutions. Build up gradually from a 4x4 to 5x5 to 6x6 grid.
Harder version: try increasing the size of the grid.

Repeat the game, aiming to find a winning strategy, then talk together about how it was found.

There's a classroom version of this game here.