Common Core standard:
Students develop an understanding of fractions, beginning with unit fractions. Students view fractions in general as being built out of unit fractions, and they use fractions along with visual fraction models to represent parts of a whole.
b. Decompose a fraction into a sum of fractions with the same denominator in more than one way, recording each decomposition by an equation. Justify decompositions, e.g., by using a visual fraction model.
Grade level: 3rd
Source 1: This is a great source that explains everything you need to know about fractions!
Source 2: Fun activities to practice fractions! Make sure you go to Fractions activities
Source 3: 3rd grade students please follow the link and from there explore only sections: <1> <4> <6> and <8>