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How do I divide a fraction by an integer?

Published in Fraction Division 2 mins read

To divide a fraction by an integer, you can rewrite the integer as a fraction and then multiply by the reciprocal, effectively "flipping" the second fraction (the integer).

Here’s a breakdown of the process, incorporating insights from the provided YouTube reference:

  1. Understand the Problem: You're starting with a fraction (e.g., 1/2) and dividing it by an integer (e.g., 3).

  2. Rewrite the Integer as a Fraction: Any integer can be expressed as a fraction by placing it over 1. For example, 3 becomes 3/1. The reference mentions that "the denominator needs to be one, and the numerator is three".

  3. Change Division to Multiplication: Division is the same as multiplying by the reciprocal. Change the division sign (÷) to a multiplication sign (×).

  4. Invert (Flip) the Second Fraction: This means swapping the numerator and denominator of the second fraction (the one you're dividing by). So, 3/1 becomes 1/3. The reference uses the term "invert or flip the second fraction".

  5. Multiply the Fractions: Multiply the numerators together and the denominators together.

    • Numerator × Numerator
    • Denominator × Denominator
  6. Simplify: If possible, simplify the resulting fraction.

Example:

Let's divide 1/2 by 3.

  1. Problem: 1/2 ÷ 3
  2. Integer as a Fraction: 3 = 3/1
  3. Change to Multiplication: 1/2 × ?
  4. Invert the Second Fraction: 3/1 becomes 1/3
  5. Multiply: 1/2 × 1/3 = (1 × 1) / (2 × 3) = 1/6
  6. Simplify: 1/6 (already in simplest form)

Therefore, 1/2 divided by 3 is 1/6.

Summary in Table Format:

Step Action Example (1/2 ÷ 3)
1. Prepare Write the problem 1/2 ÷ 3
2. Integer to Fraction Represent the integer as a fraction over 1 3 = 3/1
3. Change to Multiply Replace division with multiplication 1/2 × ?
4. Invert Flip the second fraction 3/1 becomes 1/3
5. Multiply Multiply numerators and denominators 1/2 × 1/3 = 1/6
6. Simplify (if needed) Reduce the fraction to its simplest form 1/6 (already simple)