The activity in this free math video helps build understanding of what “writing fractions in lowest terms” means. Notice I am not telling them any rules at this point. They are simply exploring the relationships within certain “families.” Eventually, they should be able to intuit the rules for themselves or, if not, at least understand why the rules make sense.
Using Cuisenaire Rods to learn about fractions gives children a visual and kinesthetic way to explore concepts that are rarely understood well. Instead of learning rules about symbols they will DISCOVER rules about the numbers that those symbols represent. (4 is not a number – it is a symbol that represents a number.)