No way, this isn't your run of the mill arithmetic. This is Pre-algebra. You're about to play with the professionals. Think of pre-algebra as a runway. You're the airplane and algebra is your sunny vacation destination. Without the runway you're not going anywhere. Seriously, the foundation for all higher mathematics is laid with many of the concepts that we will introduce to you here: negative numbers, absolute value, factors, multiples, decimals, and fractions to name a few. So buckle up and move your seat into the upright position. We're about to take off!
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Negative numbers and absolute value

Factors and multiples

Understanding and finding factors and multiples. After these videos, you'll be ready for fractions.



Ratios, proportions, units, and rates

Applying mathematical reasoning

You already have many tools in your mathematical toolkit. In this topic, you'll use these in settings that you're likely to encounter in the real world!

Exponents, radicals, and scientific notation

Understanding and solving exponents without algebra.

Arithmetic properties

This tutorial will help us make sure we can go deep on arithmetic. We'll explore various ways to represent whole numbers, place value, order of operations, rounding and various other properties of arithmetic.


From length to area to volume to time, thinking about how we measure things.

Ratios, proportions, units, and rates

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All content in “Ratios, proportions, units, and rates”


How fast can a robot possum fly? What is the rate at which a hungry you can consume avocados? This tutorial helps you make sense of these fundamental questions in life.

Metric system unit conversion

You might be surprised to realize that only two countries in the world use feet, miles, or yards or a bunch of other "English System" conventions (the irony being that the English don't even use the "English System" any more). Everyone else, including the English, now use the metric system which is actually much more logical. Learn about kilo and milli and centi and become a metric unit megastar!

Fahrenheit and Celsius conversion

There are three major conventions for measuring temperature in the world, Fahrenheit, Celsius and Kelvin. If converting between the three gives you cold feet, then this tutorial might warm them up.