Borui Academy

The Lecture System

Free Forever

Better lectures.
Higher scores.

Every chapter is built tight to the curriculum, narrated in Chinese + English, paired with YouTube walkthroughs, and stress-tested against real past papers. No fluff, no filler.

Designed for retention, not entertainment

We threw out the “long video lecture → do problems alone” loop and built something tighter.

Curriculum-aligned

Every section ID (e.g. 1.1, 4.7) maps exactly to the CollegeBoard / CEMC / CSCA outline. No off-topic detours.

Worked from real exams

Every chapter cites at least one question from a recent past paper, worked step-by-step with the trap explained.

Practice embedded

"Try it!" mini-quiz at the end of every section. Answer reveals are collapsed by default so you actually attempt them.

Narrated + on video

Chinese / EN narrated audio for each subsection. Curated YouTube videos by other creators for tricky topics — always free, always attributed.

Anatomy of a chapter

Every chapter has the same skeleton

You should never have to figure out the page layout. After 1 chapter, you know exactly where to find every component on every chapter, across every subject.

  • 🎯Learning Goals calloutWhat you can do after the chapter
  • 📚Theory sectionDefinitions, intuition, formula sheets
  • 🔑Key Insight calloutsThe trap / shortcut / mnemonic
  • ✏️Worked ExampleStep-by-step solution to a past-paper item
  • 📝"Try it!" exercisesMini quiz, answers in collapsed details tag
  • 📌Chapter SummarySkim before exam, no need to re-read everything
/csca-math/series-notes/sets-inequalities

Chapter 1

Sets & Inequalities

🎯 By the end of this chapter…

## 1.1 Set Operations

A set is a collection of distinct objects…

⚠️ The #1 trap on CSCA: 6 ∈ A vs {6} ∈ A …
🔑 Number-line trick

### Worked Example 1.1.A

📌 Chapter summary

YouTube walkthroughs

For tricky topics we curate 5–7 minute YouTube walkthroughs from the best free creatorsand embed them inline. Always with clear attribution; clicking the title takes you to the creator's channel. 100% free, even without an account.

📺 Videos credited to their original creators · embedded via YouTube's official iframe with attribution ·see attribution policy

Lecture audio (中 / EN)

Every section has a narrated audio companion — useful for review during commutes, runs, or while drawing diagrams. Chinese for ESL students, English for native speakers.

1.1 Set Operations · 中文

1:244:38

Now live for calculus-bc, gauss-7. Other courses gradually.

Outline fidelity

Every minute is on the exam.

Most prep videos drift into “here's a fun related thing” tangents. Our chapters refuse to. Each section header includes the official topic ID, so you can audit fit against the curriculum sheet in 5 seconds.

CSCA Math · Unit 1 (8% of exam)

1.1Set Operations
1.2Set-Builder & Interval Notation
1.3Linear & Quadratic Inequalities
1.4Rational Inequalities
1.5Comparing Powers & Logs

100% of past paper questions in this unit map to one of these 5 topic IDs.

Built across all our courses

The lecture system isn't a one-off — it's the engine running every subject.

45

Courses

AP · IB · CEMC · CSCA · BC bridge

363

Units

mapped to official outlines

2,045

Topics

every one drilled

18,324+

Questions

with worked solutions

Video Attribution Policy

We respect creators. Videos are free and attributed.

  • All embedded videos are via YouTube's official iframe — playback, ads, and metrics go through YouTube to the original creator.
  • Every embed shows the creator's name; clicking the title opens the video on the creator's YouTube channel.
  • Videos are not behind any paywall — anyone, signed-in or not, can watch.
  • What Borui Academy charges for is the surrounding system — Memory Curve, practice questions, mock exams, AI Tutor — not the videos themselves.
  • Creators who don't want their videos embedded can email [email protected] and we'll remove the embed within 24 h.

See how it reads

Open a sample chapter — no signup needed.