Common Core Standard 4.NF.1 Lesson Plans
In Fourth Grade Number and Operations—Fractions, Item 1, the Common Core State Standards for Mathematics reads:
Extend understanding of fraction equivalence and ordering.
Explain why a fraction a/b is equivalent to a fraction (n × a)/(n × b) by using visual fraction models, with attention to how the number and size of the parts differ even though the two fractions themselves are the same size. Use this principle to recognize and generate equivalent fractions.