Introduction to Algebra: how much does each animal weigh?

Suitable either as a short activity, or a lesson or sequence of lessons; the excel document provides two worksheets each with a set of 6 scales and a variety of animals on each. The premise is simple, students must determine the weight of each animal. This is a simple introduction to Algebra, but can be seen as a simple problem solving activity. If the teacher starts by recording the 6 sets of scales as abstract algebra (eg c = 10, 2c = h, 2c + 2h = 2d based on the first set of scales), it is easy to share with students how much easier Algebra is when dealing with concrete (animals and pictures) as opposed to abstract (numbers and letters).

To extend the students, and to create an excellent creative activity that is perfectly differentiated, ask students to create their own scales that 'build' towards a final unknown. The challenge is to ensure each scale is sequential, the 'Maths' works and the solution can be found, and the symbols or theme that the student chooses to use is manageable! I have had students create 'Christmas' themes with Father Christmas, reindeer, presents, elves etc, and students who have used simple quadrilateral shapes. They choose according to their artistic ability, and to the complexity of the problem they wish to create. Once created, the students have produced their own puzzles that their peers can attempt to solve at the beginning of the next lesson, evaluate in terms of difficulty, and offer words of advice on how the worksheet could be improved.