Set includes 1 scales, 20 weights These favour the reasoning and evolution of basic arithmetic operations Recommended age for 5 to 8 years children's Description These favour the reasoning and evolution of basic arithmetic operations. With 20 weights, numbered arms and 10 hangers on each of them. Functions through balance when there is a relation of equal weight between the 2 arms, so that the notions of calculation and equation are fully understood through practice. Available in 95 cm size.