Math Vocabulary for 3rd Grade
93 terms
JamWise Education Team·Updated March 2026
In 3rd grade, students in the upper elementary (3-5) band encounter 93 essential math vocabulary terms. These words form the foundation for classroom discussions, reading comprehension, written assignments, and standardized assessments. Mastering this vocabulary gives students the language they need to express their understanding with clarity and confidence.
Below you will find every math term for 3rd grade, organized by topic where applicable. Each term links to a detailed definition page with grade-level explanations, related vocabulary, and connections to JamWise learning resources.
algebra
View topic hubEquation
A math sentence with an equal sign showing that two sides have the same value. 5 + 3 = 8 is an equation.
Expression
A math phrase with numbers and operations but no equal sign. 4 + 7 and 3 x 5 are expressions.
Parentheses
Symbols ( ) used in math to show which operation to do first. In (3 + 2) x 4, you add first.
Pattern
A set of numbers or shapes that follows a rule and repeats or grows in a predictable way.
Unknown
A missing number in an equation that you need to figure out, often shown as a question mark or a letter.
data
View topic hubBar graph
A graph that uses bars of different heights or lengths to compare amounts of data.
Data
Information collected by counting, measuring, or asking questions, often organized in charts or graphs.
Line plot
A graph that shows data by placing marks (usually X's) above numbers on a number line.
Picture graph
A graph that uses small pictures or symbols to show data. Each picture can stand for one or more items.
Scale
The numbers along the side or bottom of a graph that help you read the data values.
fractions
View topic hubDenominator
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.
geometry
View topic hubAcute angle
An angle that is smaller than a right angle — it measures less than 90 degrees.
Cone
A 3D shape with one flat circular face and one curved surface that comes to a point.
Congruent
Having the exact same shape and size. Two shapes are congruent if one fits perfectly on top of the other.
Cube
A solid shape with 6 square faces that are all the same size, like a dice.
Cylinder
A 3D shape with two flat circular faces and one curved surface, like a can.
Hexagon
A polygon with exactly 6 sides and 6 angles.
Obtuse angle
An angle that is bigger than a right angle — it measures more than 90 degrees but less than 180 degrees.
Parallel lines
Lines that are always the same distance apart and never cross, like railroad tracks.
Pentagon
A polygon with exactly 5 sides and 5 angles.
Polygon
A flat, closed shape made of straight line segments. Triangles, rectangles, and hexagons are all polygons.
Quadrilateral
A flat shape with exactly 4 straight sides and 4 angles. Squares, rectangles, and trapezoids are all quadrilaterals.
Rhombus
A quadrilateral with 4 sides that are all the same length. It looks like a tilted square.
Right angle
An angle that makes a perfect square corner, like the corner of a book. It measures exactly 90 degrees.
Sphere
A perfectly round 3D shape, like a basketball or globe.
Trapezoid
A quadrilateral with exactly one pair of parallel sides.
Triangle
A polygon with exactly 3 sides and 3 angles.
Vertex
The point where two sides of a shape or two rays of an angle meet. A triangle has 3 vertices.
measurement
View topic hubArea
The amount of space inside a flat shape, measured in square units. A rectangle 3 units by 4 units has an area of 12 square units.
Centimeter
A small unit of length in the metric system. Your pinky fingernail is about 1 centimeter wide.
Elapsed time
The amount of time that passes between a start time and an end time.
Foot
A unit of length in the customary system. 1 foot equals 12 inches — about the length of a school ruler.
Gram
A small unit for measuring how heavy something is in the metric system. A paperclip weighs about 1 gram.
Inch
A small unit of length in the customary system. A quarter coin is about 1 inch across.
Kilogram
A unit for measuring mass in the metric system. 1 kilogram equals 1,000 grams. A textbook weighs about 1 kilogram.
Liter
A unit for measuring liquid in the metric system. A large water bottle holds about 1 liter.
Mass
The amount of matter in an object, measured in grams or kilograms.
Meter
A unit of length in the metric system. 1 meter equals 100 centimeters — about the width of a doorway.
Perimeter
The total distance around the outside edge of a shape. To find the perimeter, add up the lengths of all the sides.
Square unit
A square with sides that are each 1 unit long, used to measure area.
Tiling
Covering a flat surface completely with shapes that have no gaps or overlaps, used to find area.
Yard
A unit of length in the customary system. 1 yard equals 3 feet — about the length of a baseball bat.
operations
View topic hubAddend
A number being added to another number. In 3 + 5 = 8, both 3 and 5 are addends.
Algorithm
A set of step-by-step instructions for solving a math problem. Stacking numbers to add is an algorithm.
Array
Objects arranged in equal rows and columns. An array with 3 rows of 4 shows 3 x 4 = 12.
Associative property
A rule that says when you add or multiply three or more numbers, how you group them does not change the answer.
Commutative property
A rule that says you can add or multiply numbers in any order and get the same answer. 3 + 5 = 5 + 3.
Compare
To decide if one number is greater than, less than, or equal to another number using the symbols >, <, or =.
Difference
The answer you get when you subtract one number from another. The difference of 9 - 4 is 5.
Distributive property
A rule that lets you break apart a multiplication problem to make it easier. 3 x 7 = 3 x 5 + 3 x 2.
Divide
To split a number into equal groups. 12 divided by 3 means splitting 12 into 3 equal groups of 4.
Dividend
The number being divided in a division problem. In 12 / 3 = 4, the number 12 is the dividend.
Divisor
The number you divide by. In 12 / 3 = 4, the number 3 is the divisor.
Equal groups
Groups that have the same number of items in each one. 3 bags with 5 apples each are equal groups.
Estimate
A close guess about an amount or answer, often made by rounding numbers first.
Fact family
A set of related math facts using the same three numbers. 3, 4, 12 gives: 3x4=12, 4x3=12, 12/3=4, 12/4=3.
Factor
A number that you multiply with another number to get a product. In 3 x 4 = 12, both 3 and 4 are factors.
Multiply
To add a number to itself a certain number of times. 4 x 3 means adding four 3 times: 4 + 4 + 4 = 12.
Number line
A straight line with numbers placed at equal distances along it, used to show the order and position of numbers.
Product
The answer you get when you multiply two numbers. The product of 3 x 4 is 12.
Quotient
The answer you get when you divide one number by another. When you divide 12 by 3, the quotient is 4.
Remainder
The amount left over when a number cannot be divided evenly. 13 / 4 = 3 with a remainder of 1.
Sum
The answer you get when you add numbers together. The sum of 4 + 6 is 10.
place-value
View topic hubDigit
Any of the symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 used to write numbers.
Expanded form
A way to write a number that shows the value of each digit. 452 = 400 + 50 + 2.
Place value
The value of a digit based on its position in a number. In 352, the 3 is in the hundreds place and means 300.
Rounding
Replacing a number with a nearby number that is easier to work with. 48 rounds to 50.
Standard form
The usual way of writing a number using digits. The standard form of three hundred forty-two is 342.
Whole number
Any of the counting numbers (1, 2, 3, ...) and zero. Whole numbers have no fractions or decimals.
Word form
A way of writing a number using words instead of digits. The word form of 58 is fifty-eight.
General math terms
Analog clock
A clock with hour and minute hands that move in a circle.
Capacity
How much a container can hold.
Digital clock
A clock that shows time with numbers, not hands.
Division
Splitting a total into equal groups to find how many in each group.
Equivalent fractions
Fractions that name the same amount, like 1/2 and 2/4.
Multiplication
A faster way to add equal groups. 3 x 4 means three groups of four.
Multiplication table
A chart showing the products of numbers multiplied together.
Nearest hundred
The closest multiple of one hundred to a given number. 382 rounds to 400.
Nearest ten
The closest multiple of ten to a given number. 47 rounds to 50.
Number line fraction
Fractions shown as points on a number line between 0 and 1.
Number pattern
A list of numbers that follow a rule, like 3, 6, 9, 12.
Open number line
A blank number line you use to show jumps for adding or subtracting.
Parentheses in equations
Symbols ( ) that show which operation to do first in a math problem.
Pictograph
A graph that uses pictures or symbols to show data. Each picture can stand for more than one.
Round
To change a number to the nearest ten or hundred to make it easier to work with.
Scaled bar graph
A bar graph where each line on the scale stands for more than one.
Square number
A number you get by multiplying a number by itself. 4 x 4 = 16, so 16 is a square number.
Times
A word and sign (x) meaning to multiply.