Khan Academy on a Stick
Addition and subtraction
Adding and subtracting positive and negative whole numbers. Starts with 1+1=2 and covers carrying, borrowing, and word problems.

Basic Addition
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Introduction to addition. Multiple visual ways to represent addition.

Basic Subtraction
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Introduction to subtraction
Intro to addition and subtraction
Adding and subtracting is the basis of all mathematics. This tutorial introduces you to onedigit addition and subtraction. You might become pretty familiar with the number line too!

Example: Adding two digit numbers (no carrying)
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Adding Whole Numbers and Applications 1

Subtraction 2
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Different ways to view subtraction

Example: 2digit subtraction (no borrowing)
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Subtracting Whole Numbers

Level 2 Addition
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Adding a 2 digit number to a 1 digit number. Introduction to carrying.
Two digit addition and subtraction
In this tutorial, we'll start adding and subtracting numbers that have two (yes, two!) digits. We won't be doing any carrying or borrowing (you'll learn what those are shortly) so you can see that adding or subtracting two digit numbers is really just an extension of what you already know.

Introduction to carrying when adding
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Adding 2digit numbers

Addition 3
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Practice carrying digits to add multiple digit numbers

Addition 4
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More practice carrying with multiple digit numbers
Addition with carrying
You're somewhat familar with adding, say, 17+12 or 21+32, but what happens for 13+19? Essentially, what happens when I max out the "ones place". In this tutorial, we'll introduce you to the powerful tool of carrying and why it works.

Subtraction 3: Introduction to Borrowing or Regrouping
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Introduction to borrowing and regrouping

Why borrowing works
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An explanation of why (not how) borrowing/regrouping works when subtracting numbers
 Borrowing once example 1

Borrowing once example 2
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 Regrouping (borrowing) twice example

Alternate mental subtraction method
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How I subtract in my head

Level 4 Subtraction
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Subtraction of multidigit numbers involving borrowing
Subtraction with borrowing (regrouping)
You can subtract 21 from 45, but are a bit perplexed trying to subtract 26 from 45 (how do you subtract the 6 in 26 from the 5 in 45). This tutorial is your answer. You'll see that we can essentially "regroup" the value in a number from one place to another to solve your problem. This is also often called borrowing (although it is like "borrowing" sugar from your neighbor in that you never give it back).

Subtraction Word Problem
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Subtraction Word Problem
Addition and subtraction word problems
You feel comfortable with adding and subtracting multidigit numbers. Now you can apply some of your skills to solve problems that arise in the real world (often called "word problems").