Why Borrowing Works

An Explanation of Why (not how) Borrowing/regrouping Works When Subtracting Numbers.

Course Lectures

• Basic Addition

  Salman Khan

  Play

  Introduction to Addition. Multiple Visual Ways to Represent Addition.

• Addition 2

  Salman Khan

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  Adding 2-digit Numbers.

• Level 2 Addition

  Salman Khan

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  Adding a 2 Digit Number to a 1 Digit Number. Introduction to Carrying.

• Addition 3

  Salman Khan

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  Practice Carrying Digits to Add Multiple Digit Numbers.

• Addition 4

  Salman Khan

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  More Practice Carrying with Multiple Digit Numbers.

• Basic Subtraction

  Salman Khan

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  Introduction to Subtraction.

• Subtraction 2

  Salman Khan

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  Different Ways to View Subtraction.

• Subtraction 3: Introduction to Borrowing or Regrouping

  Salman Khan

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  Introduction to Borrowing and Regrouping.

• Alternate Mental Subtraction Method

  Salman Khan

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  How I Subtract in My Head.

• Why Borrowing Works

  Salman Khan

  Playing

  An Explanation of Why (not how) Borrowing/regrouping Works When Subtracting Numbers.

• Level 4 Subtraction

  Salman Khan

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  Subtraction of Multi-digit Numbers Involving Borrowing.

• Adding Decimals

  Salman Khan

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  Adding Decimals.

• Subtracting Decimals

  Salman Khan

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  Subtracting Decimal Numbers.

• Basic Multiplication

  Salman Khan

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  Introduction to Multiplication.

• Multiplication 2: The Multiplication Tables

  Salman Khan

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  Introduction to the Multiplication Tables From 2-9.

• Multiplication 3: 10,11,12 Times Tables

  Salman Khan

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  Multiplication 3: Learning to Multiply 10, 11, and 12.

• Multiplication 5: 2-digit Times a 2-digit Number

  Salman Khan

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  Multiplying a 2-digit Number Times a 2-digit Number.

• Multiplication 6: Multiple Digit Numbers

  Salman Khan

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  Working Our Way Up to Multiplying Multiple-digit Numbers With Each Other.

• Multiplication 7: Old Video Giving More Examples

  Salman Khan

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  2 Examples of Multiplying a 3 Digit Number Times a 2 digit Number. 1 Example of Multiplying a 3 Digit Number Times a 3 Digit Number.

• Mulitplication 8: Multiplying Decimals (Old video)

  Salman Khan

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  Multiplying decimals.

• Lattice Multiplication

  Salman Khan

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  Introduction to Lattice Multiplication.

• Why Lattice Multiplication Works

  Salman Khan

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  Understanding Why Lattice Multiplication Works.

• Division 1

  Salman Khan

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  Introduction to Division.

• Division 2

  Salman Khan

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  Dividing into Larger Numbers. Introduction to Long Division and Remainders.

• Division 3: More Long Division and Remainder Examples

  Salman Khan

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  More Long Division and Remainder Examples.

• Level 4 Division

  Salman Khan

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  Dividing a Two Digit Number into a Larger Number.

• Converting Fractions to Decimals

  Salman Khan

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  How to Express a Fraction as a Decimal.

• Percent and Decimals

  Salman Khan

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  Expressing Percentages as Decimals. Expressing Decimals as Percentages.

• Dividing Decimals

  Salman Khan

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  Dividing Decimal Numbers.

• Ordering Numeric Expressions

  Salman Khan

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  Ordering Numbers Expressed as Decimals, Fractions, and Percentages.

• Greatest Common Divisor

  Salman Khan

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  4 example Problems of Determining the Greatest Common Factor of Two Numbers by Factoring the 2 Numbers First.

• Equivalent Fractions

  Salman Khan

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  Introduces the concept of equivalent fractions.

• Mixed Numbers and Improper Fractions

  Salman Khan

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  Converting mixed numbers to improper fractions and improper fractions to mixed numbers.