Comprehensive definitions for 230+ K-12 math terms. Perfect for students, parents, and teachers.
Combining two groups to make a whole (+)
Identifying circles, squares, triangles, rectangles
Days of week, months, seasons
Counting objects, comparing quantities
Longer/shorter, heavier/lighter concepts
Comparing quantities using more, less, equal
Identifying numerals 0–20
Writing numerals correctly, number formation
First, second, third positions
Recognizing and extending patterns
Above, below, beside, next to, in front, behind
Visual addition word problems within 5 (+)
Sorting and categorizing objects
Categorizing objects by attributes
Taking away from a whole (-)
Defining and composing shapes
Identifying penny, nickel, dime, quarter
Greater than, less than, equal to (>, <, =)
Simple graphs and charts
Introduction to halves and fourths
Relating addition and subtraction
Using comparison symbols correctly (<, >, =)
Reading clocks at half-past
Non-standard and standard units
Finding unknown in equations (5 + ? = 8) (+)
Part-part-whole relationships for numbers to 10
Using number lines for addition and subtraction (+, -)
Understanding base-ten system (Decomposition by 10s)
Counting and organizing with tallies
Reading clocks to hour and half-hour
Adding three numbers together (+)
Adding numbers up to 100 (+)
Subtracting numbers up to 100 (-)
Real-world applications
Equal groups in rows and columns
Creating and interpreting data
Mixed coins (calculating totals)
Division concept introduction (÷)
Reasonable estimates for small numbers
Classifying numbers
Organizing measurement data on line plots
Using rulers to measure length
Standard units of length (in, ft, cm, m)
Adding 10, 100; subtracting 10 mentally (+, -)
Coins, dollars, and counting money ($, ¢)
Patterns in 100s chart
Understanding 3-digit place value deeply
Time to 15-minute intervals
Carrying and borrowing
Foundation for multiplication (+)
Understanding sides, vertices, angles
Counting by multiples
Reading, writing, and comparing
Reading analog and digital clocks
Measuring rectangles and squares (P=2l+2w, A=lw)
Reading and creating scaled graphs
Repeated subtraction (÷)
Understanding and calculating remainders (÷)
Time intervals and duration
Finding factors of numbers up to 100
Comparing fractions to determine which is larger (<, >, =)
Part-to-whole relationships (a/b)
Organizing categorical data
Cups, pints, quarts, gallons
Converting within same system
Repeated addition (×)
Fluency with 0-12 multiplication tables (×)
Finding perimeter of various shapes (P = sum of all sides)
Understanding multiplication properties
To nearest 10 and 100
Interpreting scales on bar graphs
Each symbol represents multiple units
Reading clocks and elapsed time
Reading thermometers, Fahrenheit/Celsius
Understanding 1/2, 1/3, 1/4, etc. (1/n)
Ounces, pounds, grams, kilograms
Measuring angles with protractor (°)
By angles (acute, right, obtuse) and sides (equilateral, isosceles, scalene)
Plotting points in first quadrant ((x, y))
Comparing decimal values (<, >, =)
Understanding tenths and hundredths
Relationship to fractions
Simplifying fractions (a/b = c/d)
Divisibility rules and factor pairs
Visual representations (number lines, area)
Ordering multiple fractions (<, >, =)
Finding greatest common factor (GCF)
Creating and interpreting data
Multi-digit divisors (÷)
Whole + fractional parts (a b/c)
2-digit × 2-digit multiplication (×)
Finding least common multiple (LCM)
Measuring angles with protractor
Approximation to nearest place (≈)
Lines of symmetry in figures
Properties of quadrilaterals and triangles
Plotting in first quadrant ((x,y))
Understanding volume units (units³)
Histograms, line graphs, stem-and-leaf plots
Operations with decimals (+, -, ×, ÷)
Dividing with decimal divisors (÷)
Powers of 10 and basic exponent notation (10ⁿ)
Writing and evaluating numerical expressions
Adding and subtracting unlike denominators (a/b ± c/d)
Multiplying and dividing fractions ((a/b) × (c/d), (a/b) ÷ (c/d))
Converting between fractions and decimals (÷)
Solving real-world problems with fractions
Creating and interpreting trends over time
Calculating and interpreting mean (sum ÷ count)
Converting between different units
Identifying rules and sequences
Sequence of operations (PEMDAS)
Parentheses, exponents, multiplication/division, addition/subtraction (PEMDAS)
Understanding percent as per hundred (%)
Multiplying/dividing by powers of 10 (10^n)
Numbers divisible only by 1 and itself
Identifying prisms, pyramids, cylinders, cones, spheres
Three-dimensional measurement (V = l × w × h)
Distance from zero (|x|)
Area of triangles and composite shapes (A = ½bh)
Reading and creating box-and-whisker plots
Plotting points ((x,y))
Using reciprocals to divide fractions (÷, reciprocal)
Visual representation for ratios and proportions
Writing and evaluating algebraic expressions
Using GCF to simplify fractions (GCF)
Frequency distributions with intervals
Positive and negative numbers
Understanding spread in data (Q3 - Q1)
Using LCM for adding fractions (LCM)
Additional measures of center
Number line with negative values
Solving simple equations (x + a = b, ax = b)
All four operations with positive and negative numbers (+, -, ×, ÷)
Finding percentages of quantities (% × n)
Per hundred relationships (% = part/whole × 100)
Speed, cost per unit, unit conversion (rate = distance/time)
Equivalent ratios in table format (a:b)
Comparing quantities (a:b = c:d)
Analyzing data distributions (mean, median, mode, range)
Nets and surface area of prisms (SA = 2lw + 2lh + 2wh)
Triangle properties and angle relationships (Sum of angles = 180°)
2D measurement (A=lw, A=πr²)
Circumference and area (C=2πr, A=πr²)
Simplifying expressions by combining terms
Angle relationships and pairs (90°, 180°)
Expanding expressions using distribution (a(b + c) = ab + ac)
Using variables (y = mx + b)
Comparing values (x > y)
Solving complex algebraic equations with multiple operations
Tax, tip, discount, markup
Percent increase and decrease ((new - old)/old × 100%)
Simple probability concepts (P(A) = favorable/total)
Direct proportion and constant of proportionality (y = kx)
Listing all possible outcomes
Proportional reasoning (scale factor)
Principal, rate, time calculations (I = PRT)
Solving multi-step equations (ax + b = c)
Circular base volume calculations (V = πr²h)
Two-variable relationships and correlation
Finding distance between two points (d = √[(x₂-x₁)² + (y₂-y₁)²])
Repeated multiplication (aⁿ)
Categorical data with two variables
Linear vs non-linear functions (y = f(x))
Identifying function types from tables/graphs
Right triangle relationships (a²+b²=c²)
Number classification and properties
Cube roots and higher-order roots (³√, ⁴√)
Correlation and trend lines
Working with very large and small numbers (a × 10ⁿ)
Visual solution method for systems
Rate of change (m=(y₂−y₁)/(x₂−x₁))
Solving linear systems (y = mx + b)
Translations, rotations, reflections, dilations
3D measurement (V=lwh)
Advanced 3D geometry volume (V = (1/3)πr²h, V = (4/3)πr³)
Solving equations with absolute value (|x| = a)
Quadratic solving method (x² + bx + (b/2)²)
Real-world exponential problems (y = a(1±r)ᵗ)
Breaking down expressions (x²+bx+c=(x+m)(x+n))
Shifts, stretches, reflections of functions (f(x) + k, f(x + h), af(x))
Input-output mapping (f(x))
Substitution, elimination, graphing methods
Basic function families (linear, quadratic, etc.)
Combining like terms (ax²+bx+c)
Parabolic relationships (ax²+bx+c=0)
Using formula to solve quadratics (x = [-b ± √(b²-4ac)]/2a)
Simplifying and operations with radicals (√x, ∛x)
Simplifying rational expressions (a/b)
Graphing and properties (y = √x)
Inscribed angles and tangent lines
Arcs, sectors, circle theorems (arc length, sector area)
Counting principles (nCr, nPr)
Probability given conditions (P(A|B) = P(A∩B)/P(B))
Probability and expected outcomes (E(X) = Σ(x·P(x)))
Bell curves and standard scores (z-score)
Chance of events (P(A)=favorable/total)
Line of best fit for data (y = mx + b)
Converting between linear equation forms (Ax + By = C → y = mx + b)
Analyzing data sets (mean, median, mode)
Graphing and solving (y > mx + b)
Ratios of sides in right triangles (sinθ, cosθ, tanθ)
Circle calculations with radians (s = rθ, A = (1/2)r²θ)
Operations with imaginary unit i (a + bi)
Equations of conic sections (parabola, ellipse, hyperbola)
Growth and decay (y=a·bˣ)
Finding and graphing inverses (f⁻¹(x))
Non-right triangles (c²=a²+b²−2abcosC)
Triangle relationships (a/sinA=b/sinB)
Inverse of exponents (logₐx=y ↔ aʸ=x)
Long division and synthetic division
Fractional exponents and radical form (x^(m/n) = ⁿ√(xᵐ))
nth term and recursive formulas (aₙ = a₁ + (n-1)d, aₙ = a₁rⁿ⁻¹)
Arithmetic and geometric series (Σ, Sₙ)
Pythagorean and reciprocal identities (sin²θ + cos²θ = 1)
Trigonometry on the unit circle (x² + y² = 1)
Vertical, horizontal, and oblique asymptotes
Composite function derivatives (dy/dx = dy/du × du/dx)
Function continuity concepts and definitions
Instantaneous rate of change (dy/dx)
Area under a curve (∫f(x)dx)
Evaluating limits of indeterminate forms (lim f/g = lim f'/g')
Approaching values in calculus (lim(x→a) f(x))
Array operations ([a b; c d])
Parametric curves and eliminating parameters (x = f(t), y = g(t))
Converting between polar and rectangular (r, θ)
Asymptotes and graphing (f(x) = p(x)/q(x))
Sum of patterns (Σaₙ)
Measure of spread (σ=√Σ(x−μ)²/n)
Vector operations and applications (⟨x,y,z⟩)