In the lesson, we will take a look at how to subtract a whole number from a fraction. Let’s walk through the examples step by step.
Content:
Before getting into this topic, don’t forget that a in fraction, the top number is the numerator, and the bottom number is the denominator. See the image below:
1) Subtract 13/4 – 3:
The key to solve this problem is to focus on the denominator of the fraction, in this case is 4. Then, we convert the whole number 3 to a fraction with a denominator of 4, multiplying 3 by 4 and dividing this product by 4.
Next, we subtract the fractions 13/4 and 12/4, it’s easy since that they have the same denominator.
The answer is 1/4. Don’t forget that 1/4 is a proper fraction given that the numerator, 1, is less than the denominator, 4.
2) Subtract 23/3 – 5:
Since the denominator of the fraction is 3, we convert the whole number 5 to a fraction with a denominator of 3, multiplying 5 by 3 and dividing that product by 3.
Then, we subtract the fractions with like denominators 23/3 and 15/3.
The resulting fraction is 8/3. Also, this is an improper fraction given that the numerator 8 is greater than the numerator 3. Finally, we can convert this improper fraction to a whole number.
The answer is 8/3 or 22/3.
Steps for subtracting a whole number from a fraction
To subtract a whole number from a fraction, follow these simple steps:
- Focus on the denominator of the fraction and convert the whole number to a fraction with that denominator.
- Subtract the fractions with like denominators.
- If the resulting fraction is an improper fraction, you can convert it to a mixed number.
Video
In the following video, I will show more examples of how to subtract a whole number from a fraction.
References
For this lesson, we have used these books:
- Tussy, K., Gustafson, D. y Koenig, D. (2013). Prealgebra (4th ed.; pp. 378-382). Cengage Learning.
If you want to see examples of subtracting a fraction from a whole number, take a look at this lesson.