Khan Academy on a Stick
Decimals
Understanding decimals conceptually, using operations with decimals, rounding and estimating with decimals, and converting decimals.

Decimal Place Value
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Decimal Place Value

Decimal Place Value 2
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Decimal Place Value 2
 Writing a decimal to represent a quantity
 Expanding out a decimal by place value
 Writing out a decimal in words

Decimals on a Number Line
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Decimals on a Number Line

Points on a number line
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Points on a number line
 Comparing decimals example 1

Comparing decimals example 2
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Comparing Decimals
 Comparing decimals example 3

Comparing decimals example 3
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u03_l1_t2_we4 Comparing Decimals
Conceptualizing decimals and place notation
You've been using decimals all of your life. When you pay $0.75 at a vending machine, 0.75 is a decimal. When you see the ratings of gymnastics judges at the Olympics ("9.5, 9.4, 7.5 (booooo)"), those are decimals. This tutorial will help you understand this powerful tool all the better. Before you know it, you'll be representing numbers that are inbetween whole numbers all the time!
 Adding decimals example 1
 Adding decimals example 2

Adding decimals example 3
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Adding Decimals

Subtracting Decimals
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Subtracting Decimals
 Adding decimals word problem

Subtracting Decimals Word Problem
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Subtracting Decimals Word Problem

Subtracting decimals (old)
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Subtracting decimal numbers
Adding and subtracting decimals
You get the general idea of decimal is and what the digits in different places represent (place value). Now you're ready to do something with the decimals. Adding and subtracting is a good place to start. This will allow you to add your family's expenses to figure out if your little brother is laundering money (perhaps literally). Have fun!

Multiplying Decimals
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Multiplying Decimals

Multiplying decimals example 2
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Multiplying Decimals 3

Multiple examples multiplying decimals
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Multiplying decimals (www.khanacademy.org)
Multiplying decimals
The real world is seldom about whole numbers. If you precisely measure anything, you're likely to get a decimal. If you don't know how to multiply these decimals, then you won't be able to do all the powerful things that multiplication can do in the real world (figure out your commission as a robot possum salesperson, determining how much shag carpet you need for your secret lair, etc.).
 Dividing completely to get decimal answer
 Dividing completely to get decimal answer example 2
 Dividing a decimal by a whole number
 Dividing a whole number by a decimal

Dividing Decimals
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Dividing Decimals

Dividing decimal
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Dividing decimal numbers
Dividing decimals
You can add, subtract and multiply decimals. You know you'd feel a bit empty if you couldn't divide them as well. But something more powerful is going to happen. If you are like us, you never quite liked those pesky remainders when dividing whole numbers. Well, those pesky remainders better watch out because they are going to be divided too!!!! Ah ha ha ha ha!!!!!

Converting fractions to decimals (ex1)
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Converting fractions to decimals (ex1)

Converting fractions to decimals (ex2)
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Converting fractions to decimals (ex2)

Converting fractions to decimals
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How to express a fraction as a decimal

Converting Fractions to Decimals Example
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Converting Fractions to Decimals

Decimals and Fractions
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Decimals and Fractions

Converting decimals to fractions 1 (ex 1)
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Converting decimals to fractions 1 (ex 2)
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Converting decimals to fractions 1 (ex 3)
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Converting decimals to fractions 2 (ex 1)
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Converting decimals to fractions 2 (ex 2)
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Converting between fractions and decimals
Both fractions and decimals are desperate to capture that little part of our heart that desires to express nonwhole numbers. But must we commit? Can't we have business in the front and party in the back (younger people should look up the word "mullet" to see a hairstyle worth considering for your next trip to the barber)? Can't it look like a pump, but feel like a sneaker? Well, if 18wheelers can turn into selfrighteous robots, then why can't decimals and fractions turn into each other?

Describing the Meaning of Percent
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Describing the Meaning of Percent

Describing the Meaning of Percent 2
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Describing the Meaning of Percent 2

Representing a number as a decimal, percent, and fraction
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Representing a number as a decimal, percent, and fraction

Converting decimals to percents (ex 1)
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Converting decimals to percents (ex 1)

Converting decimals to percents (ex 2)
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Converting decimals to percents (ex 2)

Converting percents to decimals (ex 1)
Converting percents to decimals (ex 1)

Converting percents to decimals (ex 2)
Converting percents to decimals (ex 2)
 Finding percentages example

Percent word problems
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 Taking a percentage example

Identifying Percent Amount and Base
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Identifying Percent Amount and Base

Representing a number as a decimal, percent, and fraction 2
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Representing a number as a decimal, percent, and fraction 2

Ordering numeric expressions
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Ordering numbers expressed as decimals, fractions, and percentages
Intro to percentages
At least 50% of the math that you end up doing in your real life will involve percentages. We're not really sure about that figure, but it sounds authoritative. Anyway, unless you've watched this tutorial, you're really in no position to argue otherwise. As you'll see "percent" literally means "per cent" or "per hundred". It's a pseudodecimally thing that our society likes to use even though decimals or fractions alone would have done the trick. Either way, we're 100% sure you'll find this useful.

Growing by a percentage
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Growing a quantity by a percentage

Solving Percent Problems
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U05_L2_T1_we1 Solving Percent Problems

Solving Percent Problems 2
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Solving Percent Problems 2

Solving Percent Problems 3
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Solving Percent Problems 3
Percent word problems
Whether you're calculating a tip at your favorite restaurant or figuring out how many decades you'll be paying your student debt because of the interest, percents will show up again and again and again in your life. This tutorial will expose you to some of these problems before they show up in your actual life so you can handle them with ease (kind of like a vaccine for the brain). Enjoy.

Rounding Decimals
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Rounding Decimals

Estimation with Decimals
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Estimation with Decimals
Estimating and rounding with decimals
Laziness is usually considered a bad thing. But sometimes, it is useful to be lazy in a smart way. Why do a big, hairy calculation if you just need a rough estimate? Why keep track of 2.345609 when you only need 2.35? This tutorial will get you comfortable with sometimes being a little rough with numbers. By being able to round and estimate them, it'll only add one more tool to your toolkit.

Significant Figures
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Introduction to significant figures

More on Significant Figures
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Understanding the "rules of thumb" for significant figures

Addition and Subtraction with Significant Figures
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Addition and Subtraction with Significant Figures

Multiplying and Dividing with Significant Figures
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Multiplying and dividing with significant figures
Significant figures
There is a strong temptation in life to appear precise, even when you are aren't accurate. If you precisely measure one dimension of a carpet to be 3.256 meters and eyeball the other dimensional to be "roughly 2 meters", can you really claim that the area is 6.512 square meters (3.256 x 2)? Isn't that a little misleading? This tutorial gets us thinking about this conundrum and gives us the best practices that scientists and engineers use to not mislead each other.

Multiplying a Decimal by a Power of 10
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Multiplying a Decimal by a Power of 10

Dividing a Decimal by a Power of 10
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Dividing a Decimal by a Power of 10

Dividing a decimal by a power of 10 (part 2)
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Moving the decimal to multiply and divide by 10
In our decimal number system, as we move places to the left, the place values increase by a factor of 10 (likewise, they decrease by a factor of 10 as we move rightward). This idea gets direct application when we multiply or divide a decimal number by 10 because it has the effect of shifting every place value one to the right or left (sometime seen as moving the decimal point).