Discover expert-led lessons from experienced teachers. Learn at your own pace and master new skills.
Neil Chong-Kit
Base 10 isn't a mathematical law — it's a consequence of having 10 fingers, spread globally through Napoleonic conquest rather than mathematical super...
When societies grew from simple shepherding villages into vast trading empires and armies, their old counting tools simply broke — and that crisis dro...
What happens when the digit 8 simply doesn't exist? This lesson dives into multiplication and division in number bases other than 10, showing how the ...
Ever wonder how a computer does complex math with just two digits? This lesson from Section 4.4 of OpenStax Contemporary Mathematics breaks down addit...
Every time you write a number, you're executing a compact exponential equation developed over centuries — and most people never realize it. This lesso...
Abbey Morrison
This video explores the fundamental architecture of real numbers, explaining their definition, subsets, and properties. It demonstrates how understand...
This video introduces a mysterious, incredibly valuable number whose unauthorized possession is considered a federal crime, sparking curiosity about i...
This lesson dives into rational numbers — what they are, how to recognize them, and how to work with them confidently. From college graduation rates e...
Why does the expression 4 × 2² + 3 + 5² equal 44 — and not 80, 96, or even 5,184? This lesson from Section 3.3 of OpenStax Contemporary Mathematics re...
This lesson dives into the world of integers — what they are, how to spot them, and why they matter far beyond the classroom. Using vivid analogies li...
Geometric sequences are the hidden engine behind exponential growth — from a single grain of rice doubling across a chessboard to bacteria multiplying...
Arithmetic sequences show up everywhere — from the 2.5 quintillion bytes of data added to the internet every single day, to savings plans, marathon tr...
Scientific notation is the essential tool for making sense of numbers at the extremes of our universe — from 175 zettabytes of internet data down to a...
Exponents are the mathematical equivalent of texting shortcuts like "TL;DR" — a compact way to express repeated multiplication without filling up an e...
What happens when you mistype a credit card number and the website instantly flags it as invalid — before even contacting your bank? The answer lies i...
What's the real secret behind world-record mental math? It's not a superhuman brain — it's knowing how real numbers behave. This lesson from Section 3...
What do a ancient Greek philosophical cult, an infinite decimal, and a mathematical murder legend all have in common? This lesson explores irrational ...
Discover why certain prime numbers are so valuable they've been declared illegal — and how the same math that stumped ancient scholars now protects yo...
This lesson dives into Section 1.2 of OpenStax Contemporary Mathematics, exploring how subsets and set relationships work — and why they matter far be...
This lesson from Section 2.7 of Contemporary Mathematics breaks down the structure of logical arguments, showing you how to test whether a deductive a...
De Morgan's Laws give us clean, precise ways to negate conjunctions, disjunctions, and conditional statements in logic — without awkward phrasing like...
The way you structure a logical argument can completely change how it's received — even when the underlying facts stay the same. This lesson from Sect...
What do a parent's homework rule, airline boarding, and every line of computer code have in common? They all run on the invisible contracts of mathema...
Truth tables are the ultimate tool for analyzing every possible outcome of a logical statement — and this lesson from Section 2.3 of Contemporary Math...
Discover how ordinary sentences are built on a rigid mathematical framework. This lesson from Section 2.2 of Contemporary Mathematics breaks down comp...
Logic isn't just for mathematicians — it's the hidden framework behind every debate, news headline, and persuasive claim you encounter. This lesson fr...
Stepping beyond two-set Venn diagrams, this lesson tackles the surprising jump in complexity that happens the moment a third set enters the picture — ...
This lesson explores the core set operations covered in Section 1.4 of Contemporary Mathematics: intersection, union, disjoint sets, and cardinality. ...
This lesson walks through Section 1.3 of OpenStax Contemporary Mathematics, introducing Venn diagrams as visual tools for understanding relationships ...
This lesson dives into the foundational concepts of set theory, using everyday analogies — like a kitchen drawer full of utensils — to build up to sur...
This lesson explores the sociocultural model of mental health care — the idea that effective therapy must account for a client's cultural background, ...
This lesson dives into the neuroscience and treatment of addiction, explaining why chronic substance use physically alters the prefrontal cortex — the...
Therapy looks very different depending on who needs help and why. This lesson walks through the major treatment modalities covered in Section 16.3 of ...
This lesson dives into the major types of psychological and biomedical treatments covered in Section 16.2 of OpenStax Psychology 2e. From Freud's psyc...
This lesson traces the full arc of mental health treatment — from ancient supernatural explanations and skull-drilling, through the rise and collapse ...
This lesson explores two major neurodevelopmental disorders — ADHD and Autism Spectrum Disorder (ASD) — through the lens of biology, genetics, and rea...
This lesson explores dissociative disorders — conditions in which memory and identity become profoundly disrupted through psychological, not physical,...
This lesson dives deep into schizophrenia — one of the most complex and widely misunderstood psychological disorders — drawing directly from Section 1...
This lesson explores the science behind mood and related disorders, drawing from Section 15.7 of OpenStax Psychology 2e. Through the real-world cases ...
This lesson explores the biology, psychology, and social dimensions of Posttraumatic Stress Disorder (PTSD), drawing from Section 15.6 of OpenStax Psy...
This lesson unpacks Section 15.5 of OpenStax Psychology 2e, separating the clinical reality of obsessive-compulsive and related disorders from the cas...
Anxiety is the most frequently occurring class of mental disorders, affecting 25–30% of the U.S. population over a lifetime — yet not all anxiety is h...
This lesson traces how humanity's understanding of psychological disorders shifted from supernatural explanations — demonic possession, black magic, a...
How do mental health professionals decide when a thought, feeling, or behavior crosses the line into a psychological disorder? This lesson explores th...
What separates a psychological disorder from the ordinary struggles of everyday life? This lesson dives into the surprisingly complex—and often cultur...
This lesson digs into the rigorous science of subjective well-being, challenging the cultural blueprints most of us have been handed since childhood. ...
This lesson explores the psychology and biology behind how we regulate stress, drawing from Section 14.4 of OpenStax Psychology 2e. From Seligman's cl...
This lesson explores the biology behind psychophysiological disorders — real, measurable physical conditions produced or worsened by chronic psycholog...
