Instructional Video
Khan Academy

Khan Academy: Intro to Rational and Irrational Numbers

8th Standards
Explains what rational and irrational numbers are and the difference between them. [5:55]
Instructional Video
PBS

Pbs Learning Media: Converting Rational Numbers

6th - 7th Standards
Students learn how to use division and place value to convert fractions to decimals. [1:54]
Instructional Video
Khan Academy

Khan Academy: Analyzing Structure Word Problem: Pet Store (2 of 2)

10th
Sal solves a word problem about the unknown number of bears, cats, and dogs in a pet store. This is part 2 where Sal uses an algebraic reasoning.
Instructional Video
Khan Academy

Khan Academy: Analyzing Structure Word Problem: Pet Store (1 of 2)

10th
Sal solves a word problem about the unknown number of bears, cats, and dogs in a pet store. This is part 1 where Sal uses a visual reasoning.
Instructional Video
Khan Academy

Khan Academy: Adding Rational Expression: Unlike Denominators

10th
Sal rewrites (5x)/(2x-3)+(-4x^2)(3x+1) as (-8x^3+27x^2+5x)/(2x-3)(3x+1).
Instructional Video
Khan Academy

Khan Academy: Adding & Subtracting Rational Expressions: Like Denominators

10th
Sal adds 6/(2x^2-7) + (-3x-8)/(2x^2-7) and subtracts (9x^2+3)/(14x^2-9) - (-3x^2+5)/(14x^2-9).
Instructional Video
Khan Academy

Khan Academy: Adding & Subtracting Negative Numbers

7th
Learn how to add and subtract negative numbers. The problems solved in this video are 2 - 3 = -1 and -2 - 3 = -5 and -2 + 3 = 1 and 2 - (-3) = 5 and -2 - (-3).
Instructional Video
Khan Academy

Khan Academy: Adding Negative Numbers on the Number Line

7th
Sal shows how to model 6 + (-2) using vertical number lines.
Instructional Video
Khan Academy

Khan Academy: Adding Fractions With Different Signs

7th
Use a number line to add fractions with different signs.
Instructional Video
Khan Academy

Khan Academy: Adding & Subtracting Fractions

7th
Add and subtract negative fractions with unlike denominators.
Instructional Video
Khan Academy

Khan Academy: Adding Negative Numbers Example

7th
Use a number line to add -15 + (-46) + (-29).
Instructional Video
Khan Academy

Khan Academy: Adding Numbers With Different Signs

7th
Use a number line to add 15 + (-46) + 29.
Instructional Video
Khan Academy

Khan Academy: Addition & Subtraction: Find the Missing Value (Part 1 of 2)

7th
Sal solves some missing value problems: -1 = 7 - __ and -10 + __ = -5 and 4 = -2 + __ and 6 + __ = -8.
Instructional Video
Khan Academy

Khan Academy: Addition & Subtraction: Find the Missing Value (Part 2 of 2)

7th
Sal solves more missing value problems: 4 = -8 - __ and __ - (-2) = -7 and -4 = __ - 9.
Instructional Video
Khan Academy

Khan Academy: Absolute Value as Distance Between Numbers

7th
In this video, we think about what |a-b| really means, and we verify that |a-b| = |b-a| by looking at an example.
Instructional Video
Instructional Video
Instructional Video
Khan Academy

Khan Academy: Adding & Subtracting Decimals Word Problem

6th
Let's get fancy and practice adding and subtracting decimals in the same word problem.
Instructional Video
Khan Academy

Khan Academy: Adding Decimals Word Problem

6th
Here's a simple word problem asking us to put our adding decimals skill to work.
Instructional Video
Khan Academy

Khan Academy: Adding Decimals: 0.822+5.65

6th
Sal solves 0.822+5.65 using 'standard algorithm'.
Instructional Video
Khan Academy

Khan Academy: Adding Decimals: 9.087+15.31

6th
Sal solves 9.087+15.31 using the 'standard algorithm'.
Instructional Video
Khan Academy

Khan Academy: Adding Three Decimals

6th
Sal adds 7.056+605.7+5.67 using the 'standard algorithm'.
Instructional Video
Khan Academy

Khan Academy: Absolute Value Word Problems

8th
Learn to solve word problems that ask us to apply our new absolute value knowledge.
Instructional Video
Khan Academy

Khan Academy: Addition and Subtraction With Significant Figures

8th
Learn to add and subtract with significant figures.