Grade 3Math

Defining a Fraction and Its Whole

Defining a Fraction and Its Whole teaches Grade 3 students the foundational concept that a fraction represents equal parts of a whole, and critically that the 'whole' can be any shape, set, or length. From Eureka Math Grade 3: when a whole is divided into b equal parts, each part is 1/b. The whole can be a single shape, a collection of objects, or a segment of a number line. A fraction's meaning depends entirely on identifying the correct whole — 1/4 of a large pizza is much bigger than 1/4 of a small cookie.

Key Concepts

A fraction represents a part of a whole that has been divided into equal parts. The 'whole' can be a single object or a quantity, such as length, area, mass, or volume. A unit fraction, $\frac{1}{b}$, represents one of these $b$ equal parts.

Common Questions

What is a fraction?

A fraction represents a part of a whole that has been divided into equal parts. The denominator shows the total parts; the numerator shows how many are counted.

What can the 'whole' be?

The whole can be any single object (a circle, rectangle), a collection of objects (8 apples), or a length on a number line.

Why does the meaning of a fraction depend on the whole?

1/4 of different wholes gives different actual amounts. 1/4 of 8 apples = 2 apples, but 1/4 of 100 = 25.

If a shape is divided into 6 equal parts, what is each part called?

Each part is 1/6 — one-sixth of the whole.

What does the numerator represent?

The numerator tells how many equal parts are being counted or selected.

What Eureka Math grade introduces the definition of a fraction?

Grade 3, as the foundational fraction concept in the Number and Operations—Fractions domain.