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
This game for two players comes from Ghana. However, stones that were marked for this game in the third century AD have been found near Hadrian's Wall in Northern England.
Some puzzles requiring no knowledge of knot theory, just a careful
inspection of the patterns. A glimpse of the classification of
knots and a little about prime knots, crossing numbers and knot
This game offers you an opportunity to improve your ability to estimate angles.
You can either play on your own or challenge a friend.
In both cases you will have 10 goes.
The closer you get to the target angle the more points you will score.
There are three levels:
Level $1: 0-90^\circ$
Level $2: 0-180^\circ$
Level $3: 0-360^\circ$
Full Screen Version
This game provides an engaging way to estimate angles. Instant feedback enables students to improve their estimation skills.
Ask students what they know about angles around a point. Draw out names of angles (acute, obtuse, reflex, right-angled) and landmark angles (90 degrees, 180 degrees, 270 degrees, 360 degrees).
Draw acute, obtuse and reflex angles on the board and ask students to estimate their size. Encourage justification for estimates.
Draw another five angles on the board and challenge the class to make better estimates than you can. One person from the class estimates an angle, followed by you. Measure the angle with a protractor. The closest estimate gains a point. Repeat for the other four angles.
Demonstrate the interactivity with "One Player" at Level 2 before setting the group off to work in pairs. The challenge is to score more than 50 points in 10 goes. Keep a record of the highest score on the board. How close to 100 points can any pair get? This could be a long-term challenge.
Pairs move on to Level 3 when appropriate.
Towards the end of the lesson the highest scoring pair can challenge you to a game.
What angles are easy to draw?
What strategies can you use to improve your estimates?
Pairs play the "Two Player" version of the game.
Start on Level 1. Allow students to look at a protractor.