1 min lezen
Fractions: simplifying, adding, multiplying and dividing
What a fraction means, how to simplify one, and the four operations — with a common denominator only when you need it.
Leercentrum: eenvoudige wiskundelessen
Eenvoudige uitleg van de onderwerpen waar leerlingen het meest naar vragen. Elke les begint bij het idee, werkt een voorbeeld stap voor stap uit en controleert het antwoord met de wiskunde-engine van Sumzo — en linkt daarna naar een rekenmachine en oefenvragen.
Rekenen en getallen
1 min lezen
Prime factors, GCD and LCM
Break numbers into primes, then use the prime factorisation to find the greatest common divisor and least common multiple.
2 min lezen
Square roots explained: perfect squares, surds and estimating
What a square root is, the perfect squares to know, how to simplify surds such as √180, and how to estimate roots like √65 without a calculator.
Algebra
5 min lezen
Equations: what they are and how to solve them
What an equation is, what its solution means, and how to solve equations step by step — from one-step equations to fractions and two variables.
1 min lezen
Solving linear equations
Use inverse operations to get the unknown on its own, keep the equation balanced, and always check your answer.
2 min lezen
Quadratic equations: how to solve them
Factorising, completing the square, the quadratic formula and the discriminant — and how to tell which method to use.
1 min lezen
Slope and the equation of a line
What slope measures, how to find it from two points, and how to write a line as y = mx + b.
4 min lezen
How to simplify radicals (simplest radical form)
How to simplify radicals by taking out perfect-square factors, what simplest radical form means, and how to simplify radical expressions — with checked examples.
2 min lezen
Rational equations: how to solve them
What a rational equation is, how to solve rational equations by multiplying by the lowest common denominator, and why every answer must be checked.
3 min lezen
Factoring polynomials: a step-by-step guide
The steps for factoring polynomials — common factor first, then two, three or four terms — with worked examples, each checked by multiplying back out.
3 min lezen
Solving inequalities: how to solve and graph them
Solving inequalities like equations — with one extra rule — and showing the answer on a number line, in interval notation and as a shaded region.
2 min lezen
What is a solution in math? Examples with one, none or many
A solution is a value that makes an equation true. How to check one, and examples with one solution, no solution, all real numbers and two solutions.
2 min lezen
How to solve a word problem: 5 steps that work
A five-step method for solving word problems, the key words that turn into maths, and worked examples — ages, consecutive numbers, discounts and tickets.
2 min lezen
How to graph an equation: lines, parabolas and more
Three ways to graph an equation — a table of values, slope and intercept, and key points of a parabola — with worked examples and how to match a graph to its equation.
3 min lezen
Functions: how to graph a function, domain, range and f(g(x))
Function notation, how to graph a function from its formula, how to find its domain and range, and how composite functions such as f(g(x)) work.
2 min lezen
Polynomials: how to simplify, expand and solve them
What a polynomial is, how to simplify and expand polynomials, and how to solve polynomial equations by factoring — with checked examples.
2 min lezen
Rational expressions: simplify, multiply, divide, add and subtract
What rational expressions are, their excluded values, and how to simplify, multiply, divide, add and subtract them — then solve rational equations.
2 min lezen
How to solve literal equations (rearranging formulas)
A literal equation has several letters. Solving it means isolating one of them — the same moves as an ordinary equation, with letters instead of numbers.
1 min lezen
How to simplify expressions and complex fractions
How to simplify the following kinds of expression: like terms, brackets, exponents and complex fractions (a fraction inside a fraction), each with checked examples.
1 min lezen
Find x: how to solve for x in equations, angles and triangles
The questions that say “find x” — equations, angles on a line, triangle angles, Pythagoras and similar shapes — and the one idea behind all of them.
2 min lezen
Systems of equations and graphing systems of linear inequalities
How to find the solution to a system of equations three ways, then how to graph a system of inequalities: boundary lines, shading and the overlap.
Meetkunde
1 min lezen
The Pythagorean theorem
How a² + b² = c² finds a missing side of any right triangle, plus the triples worth remembering.
1 min lezen
Area of common shapes and circles
Area formulas for rectangles, triangles, trapeziums and circles — and why the triangle formula has a half in it.
2 min lezen
Area of a trapezium (trapezoid): formula and examples
The formula for the area of a trapezium (a trapezoid in the US), why it works, and worked examples — including finding a missing height or side.
2 min lezen
Types of triangles: scalene, isosceles and equilateral
Scalene, isosceles and equilateral triangles — how to tell them apart, their angles, and how to find their area, including the area of an equilateral triangle.
1 min lezen
Polygons and quadrilaterals: is a square a quadrilateral?
Is a square a quadrilateral? Yes — and a rectangle, a rhombus and a parallelogram. How the family fits together, plus polygon angle sums and areas.
1 min lezen
Triangular prism volume, cylinders, cones and other 3D shapes
How to find the volume and surface area of a triangular prism, and the volume of cylinders and cones — one idea (area of the cross-section × length) behind most of them.
Goniometrie
1 min lezen
Trigonometry basics: SOH CAH TOA and exact values
The three trig ratios, the two special triangles that give exact values, and how degrees relate to radians.
Statistiek
1 min lezen
Averages and spread: mean, median, mode, range and standard deviation
Three ways to describe a typical value, two ways to describe how spread out data is, and when to use each.
2 min lezen
Statistics basics: z-scores, percentiles, quartiles and combinations
Three statistics skills that come up again and again: turning a z-score into a percentile, finding quartiles in a data set, and counting with the combination formula.
Analyse
1 min lezen
Derivatives and the power rule
A derivative is the slope of a curve at a point. The power rule lets you differentiate any polynomial in one line.
Lineaire algebra
2 min lezen
How to find the determinant of a 2×2 or 3×3 matrix
How to find the determinant of a matrix: the ad − bc rule for 2×2, cofactor expansion for 3×3, a shortcut for triangular matrices, and what a zero determinant tells you.
Alledaagse wiskunde
2 min lezen
How to calculate percentages: the three types of problem
How to solve percentage problems of all three kinds — a percentage of an amount, one number as a percentage of another, and percentage change — with checked examples.
1 min lezen
Ratios and proportions
Simplify ratios, share amounts in a ratio, and solve proportions — the maths behind recipes, maps and scale models.
Zo leer je wiskunde met deze lessen
- Kies hieronder een onderwerp, of zoek er een.
- Lees de korte uitleg en volg de uitgewerkte voorbeelden regel voor regel — probeer elke stap voordat je hem leest.
- Bekijk de veelgemaakte fouten, zodat je weet waar je op moet letten.
- Oefen met de gekoppelde vragen. Log in als je je voortgang wilt bewaren.
Zo ziet een eenvoudig wiskundevoorbeeld eruit
Los op.
- Trek aan beide kanten 4 af: .
- Deel beide kanten door 3: .
- Controle: . ✓
Elke les werkt zo: één kleine stap tegelijk, en een gecontroleerd antwoord.
Veelgestelde vragen
Is er een makkelijke manier om moeilijke onderwerpen te leren?
Deel elk onderwerp op in kleine stappen die je al kent. De lessen doen dat voor je — kwadratische vergelijkingen beginnen bijvoorbeeld met ontbinden vóór de abc-formule.
Hoe worden de uitgewerkte voorbeelden gecontroleerd?
De voorbeelden worden in automatische tests opnieuw opgelost door de wiskunde-engine of rekenmachines van Sumzo, zodat een fout antwoord wordt gevonden voordat een les online gaat.
Heb ik een account nodig?
Nee. Alle lessen zijn gratis te lezen. Een account bewaart alleen je oefenvoortgang.