This wonderful web-based app can be found at https://solveme.edc.org/mobiles/ and can also be downloaded from The App Store and Google Play. It is suitable for students of all ages as it challenges and develops number sense and algebraic thinking from simple situations to more complicated ones.

Students can play as a guest although there is an option to create an account and log in thus saving your details and progress.

There are 200 puzzles that develop students’ number sense from ‘Explorer’ to ‘Puzzler’ to ‘Master’. Students use the given information to find out the missing values given the fact that the mobile is balanced. For example in this mobile, we can see that the two triangle sum to 6 which means that the left side of the mobile also sums to 6. Since the hexagon is 4, it means that the lune has to be 2.

Some mobiles have a number above them which indicates the total weight of the mobile thus giving clues as to what each side of the mobile weighs. In the example below, the trapezoid must be 8 as it is half of 16, hence the heart must be 2.

As students progress through the puzzles, they will be given hints as to how to use various features. For example, the pencil and eraser feature:

You can also drag a bar to one side to create an equation:

These equations can then be visually simplified by clicking on one of the shapes and dragging it downwards:

All of these build the foundations for more formal algebraic techniques.

As the puzzles progress, they do become more intricate:

There is even the option of building your own puzzles:

SolveMe Mobiles can be used in a variety of ways in the classroom. Firstly, they could be used as individual work at a centre. Secondly, they could be used by a teacher in a small group. Finally, they could be used in a whole group situation in tis manner: Students could be grouped in threes and be assigned to work at a vertical non-permanent surface. The teacher could then display a particular problem and then let the groups figure out how to solve it. Similarities and differences in the approaches that are used can then be consolidated by the teacher into perhaps a more formal approach.