Khan Academy on a Stick
Ratios, proportions, units, and rates
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Introduction to ratios
What a ratio is. Simple ratio problems.
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Ratios as fractions in simplest form
Ratios as Fractions in Simplest Form
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Simplifying rates and ratios
Simplifying Rates and Ratios
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Ratio word problem: boys to girls
In this example, we are given a ratio and then asked to apply that ratio to solve a problem. No problem!
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Ratio word problem: centimeters to kilometers
Let's solve this word problem using what we know about ratios so far.
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Proportion validity example
Understanding Proportions
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Solving ratio problems with tables example 1
We're displaying ratios in a table format here, and then asking: given a ratio, solve for equivalent ratios. Here are a few examples to practice on.
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Solving ratio problems with tables example 2
Let's compare 2 tables of ratios and interpret them to solve the word problem. This is a fun!
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Solving ratio problems with graph
In this example we'll plot points on the x and y axis to reflect the given ratios.
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!
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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.
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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.
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Solving unit price problem
Using our knowledge of fractions, we can solve this unit price problem. Remember to keep your units of measure consistent.
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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.
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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!
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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.
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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.
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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.
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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.
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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.
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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?"
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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.
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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!
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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.
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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.
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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).
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Unit conversion within the metric system
Metric unit conversion
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Converting within the metric system
Converting within the metric system
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Perimeter and unit conversion
Perimeter and Unit Conversion
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Applying the metric system
U06_L2_T3_we1 Applying the Metric System
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Conversion between metric units
Conversion between metric units
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U.S. customary and metric units
U.S. Customary and Metric units
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!
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Converting Fahrenheit to Celsius
Converting Fahrenheit to Celsius
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Comparing Celsius and Fahrenheit temperature scales
Comparing Celsius and Fahrenheit temperature scales
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.