fractions Vocabulary
JamWise Education TeamยทUpdated March 2026
The fractions strand is a core part of the K-8 math curriculum. It encompasses 22 vocabulary terms that students encounter as they progress from kindergarten through 8th grade. Each term builds on previous knowledge, creating a spiral of deepening understanding that prepares learners for increasingly complex concepts.
Understanding fractions vocabulary is essential for classroom discussions, assessments, and real-world application. Below you will find every term organized by grade level, so teachers and parents can quickly identify which words are appropriate for their students and explore definitions tailored to each developmental stage.
2nd Grade
(6 terms)
Fourths
Four equal parts that make a whole. Also called quarters.
Fraction
A number that shows part of a whole. Like one half or one third.
Halves
Two equal parts that make a whole.
Partition
To divide a shape into equal parts.
Thirds
Three equal parts that make a whole.
Whole
All the parts together. The complete thing.
3rd Grade
(6 terms)
Denominator
The bottom number in a fraction. It tells how many equal parts the whole is divided into. In 3/4, the denominator is 4.
Equivalent fraction
Fractions that name the same amount, even though they use different numbers. 1/2 and 2/4 are equivalent.
Fraction
A number that shows equal parts of a whole. In the fraction 3/4, the whole is split into 4 equal parts and you have 3 of them.
Numerator
The top number in a fraction. It tells how many equal parts you have. In 3/4, the numerator is 3.
Partition
To divide a shape or set into equal parts. You can partition a circle into 4 equal parts to show fourths.
Unit fraction
A fraction with 1 as the numerator. 1/2, 1/3, and 1/4 are all unit fractions.
4th Grade
(12 terms)
Benchmark fraction
A common fraction used to estimate and compare, like 1/4, 1/2, and 3/4.
Common denominator
A shared denominator used when comparing or adding fractions. To add 1/3 and 1/4, use the common denominator 12.
Decompose
To break a number or fraction into smaller parts. You can decompose 3/4 into 1/4 + 1/4 + 1/4.
Denominator
The bottom number of a fraction that tells how many equal parts the whole has been divided into.
Equivalent fractions
Fractions that represent the same amount. 1/2, 2/4, and 3/6 all show the same part of a whole.
Fraction
A number that names part of a whole or part of a group. The top number (numerator) tells the parts you have; the bottom (denominator) tells total equal parts.
Improper fraction
A fraction where the numerator is bigger than the denominator, meaning it is more than one whole. 7/4 is improper.
Like denominators
Fractions that have the same bottom number. 2/5 and 4/5 have like denominators (both are fifths).
Mixed number
A number made up of a whole number and a fraction together. 2 and 3/4 is a mixed number.
Numerator
The top number of a fraction that tells how many equal parts are being counted.
Unit fraction
A fraction with a numerator of 1, like 1/2, 1/3, or 1/8. It names one equal part of a whole.
Unlike denominators
Fractions with different bottom numbers, like 1/3 and 1/4. You must find a common denominator before adding or subtracting them.
5th Grade
(6 terms)Common denominator
A shared number used as the denominator when adding or subtracting fractions with different denominators.
Improper fraction
A fraction where the numerator is greater than or equal to the denominator, representing a value of 1 or more. 7/4 equals 1 and 3/4.
Mixed number
A number written as a whole number and a fraction together, like 3 and 1/2.
Simplest form
A fraction where the numerator and denominator have no common factor other than 1. The simplest form of 4/8 is 1/2.
Unit fraction
A fraction with a numerator of 1, such as 1/5 or 1/12. It represents exactly one equal part of a whole.
Unlike denominators
Fractions that have different bottom numbers, like 1/3 and 1/5. To add them, you need to find a common denominator first.