This resources brings a popular old resource up to date. As well as being smartened up this resource is compatible with iPads and other tablets as well as PCs. In essence it is the same as the older resource and is made to accompany a puzzle published in an old book by Henry Ernest Dudeney. The puzzle is a useful one for teaching deeper mathematical thinking because while it can be solved by trial and error, thinking about the maths behind it can make it much easier.
The goal is to choose a number that all 4 sides of the frame can add up to and arrange the cards to do this. Some numbers are possible some numbers are not. This puzzle has been selected as it allows students of all abilities to have a go as the maths involved is not difficult. The challenge should be to find a method of determining what numbers can be used as the common total amount, and then how to make finding the layout much easier. The resource provided here allows the puzzle to be demonstrated easily and can also allow whole class discussion of how to approach the problem. Clicking on one card and then another causes them to swap places. The resource totals the different lines automatically. Tapping the chalkboard brings up brief instructions.
If you would like the solution and teaching notes to this puzzle please contact me on twitter as this makes it much easier to see if it is a teacher or a child cheating on homework! If you don’t use twitter leave a request in the comments but this will take longer to receive a response.
This resource does not work with Internet Explorer 9. On Windows please upgrade to IE 10 or use Chrome or Firefox. Or use the original version of this resource linked to above.
HTML5 performance is still not quite there yet so on some devices this resource may lag slightly.