Bar modelling is used to help understand how to solve problems in various mathematical topics including ratio, proportion, and equations.

Linda C. Fisher, Strategies Used by Secondary Mathematics Teachers to Solve Proportion Problems, Journal for Research in Mathematics Education, Vol. 19, No. 2 (Mar., 1988), pp. 157-168 ...

Learn how proportional relationships look on a graph, understand proportionality using worked examples, and for Higher tier, revise algebraic proportion.