Author Archives: hangtime

Venn Diagrams with Numbers

This video covers the type of Venn Diagram question where each region of the diagram contains a number which represents how many people fall into that category, such as by liking chocolate or vanilla or both. This is a Common Core question that can also show up on the SAT, so get ready to think logically!

This video appears on the page: Venn Diagrams

Intro to Venn Diagrams

This video covers the basic two-circle Venn diagrams and shows you how to draw them for intersections, unions, and subsets.

This video appears on the page: Venn Diagrams

Venn Diagrams
Intro to Venn Diagrams
Venn Diagrams with Numbers
Venn Diagrams with Complements
Tough 3-Way Venn Diagrams

This chapter covers Venn diagrams in all their glory: two-circle, three-circle, complements, universes, intersections, unions, shading problems, numbers, members. Even covers the Common Core question about Venn diagrams!

Part of the course(s): Middle School Math ,Pre-Algebra Class Page

Mode of a set (SAT)

This video explains how to identify the mode of a set of numbers. For easy problems, finding the mode is simple, but this video also covers the couple of curve balls that teachers (and the SAT) usually throw at you.

This video appears on the page: Mean, Median & Mode ,Measures of Central Tendency — Mean, Median, Mode & Midrange

Median of a set (SAT)

This video focuses on the best process to find the median of a set while making the least mistakes possible, whether you're trying to find the median of a set with an even or odd number of members. Also covered is a particular type of logic question that shows up on the SAT, where they ask you "which of the following" you can do to a set without changing the median.

This video appears on the page: Mean, Median & Mode

Calculating The Mean (Average) (SAT)

This video starts with how to find the average of a group of numbers, but then it gets into trickier word problems using the average formula. Also covered are SAT-style average word problems where they ask you to solve for a missing number based on the average of the rest of the group, or where you're supposed to say what the biggest member of a set could be based on the average of all the numbers.

This video appears on the page: Mean, Median & Mode

Weighted Averages (a.k.a. figuring out your grade)

Whether you realize it or not, the weighted mean is used in every class you've ever been in: it's how your teacher calculates your grade based on how much each section of the class is worth (tests, homework, etc.)! So that's the main example we'll use in this video. And as an added bonus, we'll learn how to figure what grade you need on the final in order to get a certain grade for the semester.

This video appears on the page: Mean, Median & Mode

Mean, Median, Mode, & Weighted Averages (SAT)
Mode of a set (SAT)
Median of a set (SAT)
Calculating The Mean (Average) (SAT)
Weighted Averages (a.k.a. figuring out your grade)

More fun with sets. Also included in this topic: how to use weighted averages to figure out what grade you need on the final!

Part of the course(s): Middle School Math ,Pre-Algebra Class Page

Union vs Intersection

This video uses lots of types of examples to illustrate the union and intersection between sets: word problems, Venn diagrams, and your old friend "sets A and B".

This video appears on the page: Intro to Set Notation

Set Builder vs Interval Notation

This is the big bad voodoo daddy of set notation. If you're not at least in Algebra 2 or College Algebra you probably won't cover this, but if you do cover set builder notation, it's a topic that really sets teachers apart from each other. Some teachers are real sticklers for being "proper" with their math, and they'll beat this topic into the ground. The more student-friendly teachers will teach you this but move on because they know it's unnecessarily confusing for most students.

This video appears on the page: Intro to Set Notation

Subsets

This video covers how to determine if one set is a subset of anther one, and the types of word problems you can get from these problems. It also covers a few trick questions, such as whether a set is a subset of itself or an identical set.

This video appears on the page: Intro to Set Notation

N,Z,R,Q

"R" you've probably seen before, the big cursive script-looking R that means "real numbers". The other three represent the integers, natural counting numbers, and rational numbers which form the basis of set-builder notation.

This video appears on the page: Intro to Set Notation

Basic Set Rules

This video focuses on sets and elements, along with a bunch of typical questions which a teacher can use to get tricky on the test. Special cases, what to do when both sets have the same members, what's an element of what, etc.

This video appears on the page: Intro to Set Notation

Intro to Set Notation

In this video we'll explore what sets are, and we'll tell you what some of the key symbols and letters mean so you know which in-depth videos to look for: N, Q, Z, R, U, intersection, etc.

This video appears on the page: Intro to Set Notation

Set Notation
&
Set Builder Notation
Intro to Set Notation
Basic Set Rules
N,Z,R,Q
Subsets
Set Builder vs Interval Notation
Union vs Intersection

These videos cover everything about sets: elements, subsets, intersection, union, Venn diagrams, R, Z, Q, N. And set builder notation such as {x E R|x<5}.

Part of the course(s): Middle School Math ,Pre-Algebra Class Page

Interval Notation

This is the thing where you use ( )'s and [ ]'s and ( ]'s and [ )'s to write down a chunk of the number line.

Part of the course(s): Middle School Math ,Pre-Algebra Class Page

Balancing Redox Reactions

This video shows you how to do one of the most complicated types of problems you'll see in chemistry: balancing reduction oxidation equations using the ion-electron method. These problems are super tedious, and it's easy to make mistakes because there are so many steps. But on the bright side these redox problems are completely plug-and-chug, so once you get it down it's pretty difficult to get burned.

This video appears on the page: Balancing Redox Reactions

Balancing Redox Reactions

This chapter covers one of the most complicated types of problems you'll find in your first year of chemistry: balancing reduction oxidation equations using the ion-electron method.

Part of the course(s): Chemistry-General

How to Identify Reducing & Oxidizing Agents

This video covers a very specific type of problem which most chemistry students find confusing: labeling the oxidizing and reducing agents. What makes it tough is that the compound that gets oxidized is also the reducing agent, and the compound that gets reduced is the oxidizing agent. Confused yet? You're not the only one.

This video appears on the page: Reducing & Oxidizing Agents

Reducing & Oxidizing Agents

This video covers a very specific type of problem which most chemistry students find confusing: labeling the oxidizing and reducing agents.

Part of the course(s): Chemistry-General