The equivalence of Fractions!
This video addresses the following standards:
3.NF (Explain equivalence of fractions in special cases, and compare fractions by reasoning about their size.)
4.NF (Explain why a fraction a/b is to a fraction (n X 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.)
5.NF (Add and subtract fractions with unlike denominators (including mixed numbers) by replacing given fractions with equivalent fractions in such a way as to produce an equivalent sum or difference of fractions with like demoniators.)