Use unit fractions to compose and decompose fractions with models and symbols
When composing and decomposing fractions using unit fractions, students develop fractional number sense (quantity) that connects to their prior experience with whole numbers.
A unit fraction is the base unit of any fraction and always has a numerator of 1; for example, 1⁄4, 1⁄15, 1⁄23 are all unit fractions. Every fraction can be decomposed into unit fractions. For example, 3⁄4 is 3 one-fourth units (so one-fourth is the unit fraction and we are thinking about 3 of them). Partitioning a model involves determining and creating a unit fraction.
Consider the fraction one and three-fourths. This number can be decomposed using a unit fraction.
One and two-fourths can be composed using a unit fraction.