Rachel
About

Khan Academy on a Stick

Pre-algebra

Ratios and proportions

Would you rather go to a college with a high teacher-to-student ratio or a low one? What about the ratio of girls-to-boys? What is the ratio of eggs to butter in your favorite dessert? Ratios show up EVERYWHERE in life. This tutorial introduces you to what they (and proportions) are and how to make good use of them!

  • Finding average speed or rate

    Using the formula for finding distance we can determine Usian Bolt's average speed, or rate, when he broke the world record in 2009 in the 100m. Watch.

  • Solving unit rates problem

    Finding a unit rate is a skill often required in real life. How fast is that plane flying? How many lawns can you mow in an afternoon? You see, with our knowledge of ratios and fractions, we can now solve unit rates problems like this.

  • Solving unit price problem

    Using our knowledge of fractions, we can solve this unit price problem. Remember to keep your units of measure consistent.

  • Multiple rates word problem

    Sometimes you'll need to solve for multiple parts of the equation before getting at the answer. Here we solve for average speed, but first we have to determine total distance and total time.

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.

  • Converting pounds to ounces

    We can't tell you how many times in your life you will stare at a recipe and then need to use this skill. Trust us. Let's convert pounds to ounces!

  • Unit conversion: gallons to quarts, pints, and cups

    What's the difference between gallons, quarts, pints, and cups? Soooo many people go their entire lives without knowing how to convert one unit of measure to another. Take note.

  • Converting yards into inches

    Converting units of measure is a skill you'll encounter many times over in everyday life. In this example, we'll look at yards, feet, and inches.

  • Unit conversion: arithmetic calculations on units of volume

    Sometimes we have different units of measure and are asked to add them up. The answer can't be stated in ALL units so we have to pick one unit of measure. In this example, you'll practice that scenario with us.

  • Unit measurement word problem: weight

    We're moving between units of weight in this word problem. Ever get in an elevator with a bunch people and wonder to yourself, "How many people can this elevator safely hold?" Yeah, us too. You can solve that problem now.

  • Unit measurement word problem: converting units

    Pints or gallons? Gallons or quarts? Confused? You won't be for long. This unit measurement word problem gets us thinking about moving between these units of volume.

  • Unit conversion word problem: roadtrip

    The challenge in a word problem sometimes is knowing which numbers to choose when creating a simple equation. In this unit conversion word problem we'll answer the common question: "How much will a road trip cost me in gas?"

  • Multi-step unit conversion word problem

    The fate of a squirrel is in your hands as it tries to run across the road before a car reaches it. Use what you know about unit conversion to help solve this word problem.

  • Unit measurement word problem: running laps

    Remember that it's always easier to convert everything to like units before tackling a unit conversion word problem. That way your comparing apples to apples. Go for it...we'll explain as we work through it!

  • Unit conversion word problem: drug dosage

    Future doctors and nurses out there, take note. This unit conversion word problem deals with converting drug dosage units, something that is commonly done in hospitals. Give it a try with us.

  • Unit conversion word problem: yards to inches

    In this example, we need to convert from yards to inches. We'll do it a couple of ways.

  • Speed translation

    Translating speed units

Unit conversion

Wait, I'm in Europe and my car only tells my distance traveled in kilometers! But I'm used to a units of distance devised by the Romans to measure the average length of 1000 paces of a soldier (the "mile")! How do I operate? This tutorial is about the fundamental skill of unit conversion. Sal's cousin Nadia being a bit confused with this was actually the reason why he started tutoring her (which led to the creation of the Khan Academy).

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.