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Last updated on September 1, 2025
The mathematical operation of finding the difference between a fraction and a whole number is known as the subtraction of a fraction with a whole number. It helps simplify expressions and solve problems that involve fractions, whole numbers, and arithmetic operations.
Subtracting a fraction from a whole number involves converting the whole number to a fraction with the same denominator as the fraction.
You then perform the subtraction by subtracting the numerators and keeping the common denominator.
There are two components involved:
Fractions: These consist of a numerator and a denominator, like 3/4, where 3 is the numerator and 4 is the denominator.
Whole Numbers: These are numbers without fractions or decimals, like 5, 8, etc.
Operators: For subtraction, the operator is the minus (-) symbol.
When subtracting a fraction from a whole number, follow these steps:
Convert the whole number: Change the whole number to a fraction with the same denominator as the given fraction.
Subtract the numerators: Subtract the numerator of the fraction from the numerator of the converted whole number.
Simplify the result: Simplify the resulting fraction if possible to get the final answer.
The following method is used for subtraction of a fraction with a whole number:
Convert and Subtract Method
Step 1: Convert the whole number to a fraction with a denominator equal to that of the given fraction.
Step 2: Perform the subtraction by subtracting the numerators, keeping the common denominator.
Step 3: Simplify the resulting fraction if possible.
Let’s apply these steps to an example:
Question: Subtract 3/5 from 4.
Step 1: Convert 4 to 20/5 to have a common denominator.
Step 2: Subtract the numerators: 20 - 3 = 17, keeping the denominator as 5.
Answer: 17/5
In subtraction involving fractions and whole numbers, some characteristic properties exist.
These properties are: Subtraction is not commutative
In subtraction, changing the order of numbers changes the result, i.e., A - B ≠ B - A.
Subtraction is not associative Unlike addition, we cannot regroup in subtraction.
When three or more numbers are involved, changing the grouping changes the result.
(A − B) − C ≠ A − (B − C)
Converting whole numbers to fractions When a whole number is involved in subtraction with a fraction, it must be converted to a fraction with an equivalent denominator.
Subtracting zero from a number leaves the number as is Subtracting zero from any number results in the same number: A - 0 = A
Tips and tricks are useful for students to efficiently handle subtraction of fractions with whole numbers. Some helpful tips are listed below:
Tip 1: Always convert the whole number to a fraction with the same denominator before subtracting.
Tip 2: Simplify the resulting fraction, if possible, to get the final answer.
Tip 3: Use visual aids like fraction strips to better understand the subtraction process for beginners and visual learners.
Students often forget to convert the whole number to a fraction with the same denominator as the given fraction. Always ensure conversion before subtracting.
Convert 5 to 15/3. (15/3) - (2/3) = 13/3
Subtract 1/4 from 7
27/4
Convert 7 to 28/4. (28/4) - (1/4) = 27/4
Subtract 5/6 from 8
43/6
Convert 8 to 48/6. (48/6) - (5/6) = 43/6
Subtract 3/8 from 10
77/8
Convert 10 to 80/8. (80/8) - (3/8) = 77/8
Subtract 9/10 from 3
21/10
Subtraction involving fractions and whole numbers can be challenging, often leading to common mistakes. However, being aware of these errors can help students avoid them.
Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.
: She loves to read number jokes and games.