Free math lessons · English & Tiếng Việt
Math, one small step at a time.
Clear lessons with worked examples, pictures and practice problems with full solutions. They follow Vietnam’s grade 1–12 curriculum, in English and Vietnamese.
Pick your grade
Primary school
Grades 1–5 · Tiểu học
Lower secondary
Grades 6–9 · THCS
Upper secondary
Grades 10–12 · THPT
Why you will like it
Step by step
Every idea starts with a picture or a simple example, then the rule, then more examples.
Two languages
Read the same lesson in English or Tiếng Việt and switch with one click.
Practice with solutions
Each lesson ends with graded exercises. Open a solution only when you are ready.
Keeps your progress
Tick off lessons as you finish them. Your progress stays on your own device.
Grade 10: the complete course
Statements and sets
The basic logic of mathematics and the language of sets.
Chapter 2Linear inequalities and systems in two variables
Shading solution regions on the coordinate plane.
Chapter 3Trigonometry in triangles
Trig values, the laws of cosines and sines, and triangle area.
Chapter 4Vectors
From the idea of a vector to coordinates and the dot product.
Chapter 5Summary statistics for ungrouped data
Approximations, error, mean, median and standard deviation.
Chapter 6Functions, graphs and applications
Functions, the quadratic function, sign of quadratics and related equations.
Chapter 7Coordinate geometry in the plane
Lines, circles and the three conic sections.
Chapter 8Combinatorics
Counting rules, permutations, combinations and the binomial theorem.
Chapter 9Classical probability
Events and probability when outcomes are equally likely.