SubjectFoundations to advanced
Mathematics
Build number sense, algebraic thinking, geometry, statistics, and problem-solving confidence.
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SubjectExplore how the world works
Science
Learn physics, chemistry, biology, and earth science through clear explanations and practice.
Open resourceSubjectCode, systems, and AI
Computer Science
From first programming concepts to algorithms, software engineering, cloud, and artificial intelligence.
Open resourceSubjectProfessional learning
Cloud Computing
Architecture, operations, security, DevOps, and certification-oriented learning for modern cloud careers.
Open resourceSubjectRead, write, communicate
Language Arts
Strengthen reading comprehension, grammar, vocabulary, writing, and communication at every stage.
Open resourceSubjectPrepare for what is next
Career Skills
Interview preparation, professional communication, leadership, and role-specific knowledge.
Open resourceCourseMathematics · Beginner · Kindergarten
Kindergarten Math Foundations
A friendly introduction to counting, shapes, patterns, comparison, and early addition.
Open resourceTutorialKindergarten Math Foundations · 6 min
Counting to 20
Learn to count objects and numbers in order.
Open resourceMCQKindergarten Math Foundations · 5 min
Shapes Around Us
Practice recognizing circles, squares, triangles, and rectangles.
Open resourceArticleKindergarten Math Foundations · 7 min
What Addition Means
A visual introduction to putting groups together.
Open resourceCourseMathematics · Grade 5 · School
Grade 5 Mathematics
Core grade-level learning across fractions, decimals, geometry, measurement, and data.
Open resourceTutorialGrade 5 Mathematics · 14 min
Fractions Explained
Understand equivalent fractions, comparison, and operations.
Open resourceMCQGrade 5 Mathematics · 10 min
Decimals Checkpoint
Test place value and decimal operations.
Open resourceGuideGrade 5 Mathematics · 12 min
Volume: A Practical Guide
Learn how volume works with visual examples and formulas.
Open resourceCourseScience · Intermediate · High School & College
Physics: Mechanics Foundations
Build intuition for motion, forces, energy, momentum, and the mathematical models behind mechanics.
Open resourceTutorialPhysics: Mechanics Foundations · 18 min
Newton’s Laws Without the Mystery
A conceptual and mathematical tour of the three laws.
Open resourceMCQPhysics: Mechanics Foundations · 15 min
Mechanics Practice Set
Check understanding across motion, forces, and energy.
Open resourceNotesPhysics: Mechanics Foundations · 8 min
Free-Body Diagram Notes
A concise reference for drawing and solving force diagrams.
Open resourceCourseComputer Science · Beginner · Students & Professionals
Python Programming Foundations
Learn Python through practical examples covering syntax, data structures, functions, files, and problem solving.
Open resourceTutorialPython Programming Foundations · 12 min
Your First Python Program
Start with variables, input, output, and simple decisions.
Open resourceArticlePython Programming Foundations · 16 min
Python Data Structures
Choose between lists, tuples, sets, and dictionaries.
Open resourceMCQPython Programming Foundations · 12 min
Python Basics Quiz
Review syntax, loops, functions, and collections.
Open resourceCourseComputer Science · Beginner to Intermediate · Students & Professionals
SQL & Relational Databases
Learn how relational databases model data, how SQL retrieves and changes it, and how indexes and transactions shape correctness and performance.
Open resourceTutorialSQL & Relational Databases · 18 min
Relational Data Modeling and Keys
Turn real-world entities and relationships into tables, primary keys, foreign keys, and constraints.
Open resourceGuideSQL & Relational Databases · 22 min
SQL Query Reasoning: Joins, Groups, and Filters
Build queries by reasoning about row sets, join cardinality, grouping, and the order of logical operations.
Open resourceNotesSQL & Relational Databases · 16 min
Indexes and Transactions: Practical Notes
A concise reference for B-tree indexes, selectivity, ACID properties, isolation, locking, and common performance traps.
Open resourceCourseCloud Computing · Intermediate to Advanced · Professionals
AWS Solutions Architect
Architecture-focused AWS learning spanning identity, compute, networking, storage, reliability, security, and cost.
Open resourceTutorialAWS Solutions Architect · 22 min
IAM Architecture Essentials
Design identity boundaries, roles, policies, and access patterns.
Open resourceInterviewAWS Solutions Architect · 25 min
AWS Architecture Interview Questions
Scenario-based questions with reasoning frameworks.
Open resourceMCQAWS Solutions Architect · 18 min
Resilient Design MCQs
Test availability, scaling, storage, and disaster-recovery decisions.
Open resourceCourseCareer Skills · Advanced · Software Professionals
System Design Interview
A structured path for designing scalable systems and explaining tradeoffs clearly in technical interviews.
Open resourceGuideSystem Design Interview · 20 min
A Repeatable System Design Framework
A step-by-step structure for approaching design interviews.
Open resourceInterviewSystem Design Interview · 28 min
Design a URL Shortener
Walk through requirements, data model, APIs, scaling, and failure modes.
Open resourceNotesSystem Design Interview · 14 min
Core System Design Concepts
Fast reference for caching, queues, partitioning, consistency, and observability.
Open resourceCourseLanguage Arts · Intermediate · Students & Professionals
Professional English Communication
Write and speak with greater clarity at work through concise email, useful status updates, effective meetings, and constructive difficult conversations.
Open resourceTutorialProfessional English Communication · 15 min
Professional Email Writing
Structure email so readers understand the purpose, context, action, and deadline quickly.
Open resourceGuideProfessional English Communication · 16 min
Meetings and Status Updates That Move Work Forward
Communicate outcomes, risks, decisions, and ownership without drowning people in activity.
Open resourceArticleProfessional English Communication · 18 min
Difficult Conversations at Work
Disagree, give feedback, and raise risks using evidence, impact, and concrete next steps.
Open resourceCommandGit · reviewed 2026-08-16
git rebase
Learn git rebase through commit-graph reasoning, safe examples, conflict recovery, interactive cleanup, and practical guidance on when rebasing is the wrong choice.
Open resourceCommandGit · reviewed 2026-08-16
git merge
Learn git merge through commit-graph reasoning, fast-forward behavior, merge commits, conflict recovery, and safe collaboration scenarios.
Open resourceTroubleshootingGit · reviewed 2026-08-16
Git rebase conflict
Fix Git rebase conflicts safely by identifying the replayed commit, resolving intent instead of markers, testing the result, and knowing when to abort.
Open resourceComparisonDecision guide · reviewed 2026-08-16
Git rebase vs merge
Compare Git rebase and merge through commit-graph reasoning, collaboration safety, conflict behavior, history trade-offs, and practical decision scenarios.
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