When using fraction strips how do you know that two fractions are equivelent

Fraction strips are mathematical manipulatives: objects that students can touch, feel and move around in order to learn mathematical concepts. Fraction strips are pieces of paper cut in various sizes to show the fraction's relationship to the whole unit. For example, a set of three 1/3 fraction strips placed side by side would make one whole unit. If you make or buy sets of fraction strips that are based on units of the same size, you can compare the strips representing different fractions.